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NORTHERN LINE EXTENSION TO BATTERSEA AND NINE ELMS: FEASIBILITY STUDY AND BUSINESS CASE METHODOLOGY

Final Report

December 2008

Prepared for: Prepared by:

REO (Power Station) Ltd 188 Kirtling Street London SW8 5BN

Steer Davies Gleave 28-32 Upper Ground London SE1 9PD +44 (0)20 7919 8500 www.steerdaviesgleave.com

Final Report

P:\Projects\7400s\7466\207466-H\Outputs\Final Report\Final version to Client\Northern Line Extension to Battersea & Nine Elms - Feasibility Study and Business Case Methodology - Final Report.doc

Contents

Contents Page

1. INTRODUCTION AND SUMMARY 5

Summary 5

2. PATRONAGE FORECASTS 17

Proposed Approach to Patronage Forecasting 17

Trip Generation for Battersea Power Station & Nine Elms Corridor 18

Background Trips 19

Initial Patronage Estimation (to inform Design Parameters) 19

3. SCHEME DEVELOPMENT 22

Tunnel Alignments 31

Ventilation and Evacuation 32

Summary Approach to Construction 33

Summary Construction Programme 34

4. TRAIN OPERATIONS 39

Existing Service Pattern 39

Tube Lines Service Improvement 40

Proposed Partial Separation of the Northern Line 41

Runtimes 42

Capacity of Battersea Terminus 45

Fleet Requirements 45

5. COST ESTIMATES 48

Capital Costs by Route Option 48

Operating Costs 50

6. ENVIRONMENTAL IMPACTS AND CONSTRAINTS 51

Overview of Key Environmental Considerations and Impacts 51

Summary of Environmental Considerations & Preliminary Assessment of Impacts54

Conclusions of Preliminary Environmental Assessment 58

7. BUSINESS CASE METHODOLOGY 61

Scenarios to Be Tested 61

Costs 62

Journey Time Benefits and Revenues 62

Business Case Appraisal Framework 63

Consideration of Wider Economic Benefits 63

8. PROJECT RISKS 64

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Process to Date 64

9. NEXT STEPS 66

Forward Programme of Scheme Development 66

FIGURES

Figure 1.1 Vauxhall/North East Battersea (VNEB) Opportunity Area 7

Figure 1.2 Northern Line Extension Options 10

Figure 1.3 Existing PTAL 15

Figure 1.4 PTAL with Tube Extension to Battersea & Nine Elms (option 2 shown) 15

Figure 3.1 Options for Location of Connection at Kennington 27

Figure 3.2 Potential Nine Elms Station Locations 29

Figure 3.3 Summary estimated construction programme: Route Option 1 35



Figure 4.1 Existing Northern Line Service Pattern AM and PM peak 39

Figure 4.2 Existing Northern Line Service Pattern off-peak 40

Figure 4.3 2012 Proposed Service Improvement with new signalling AM and PM peak 41

Figure 4.4 Partial Serparation of the Northern Line AM AND PM Peak 42

Figure 9.1 Provisional TWAO Programme 67

TABLES

Table 1.1 Work Areas/Lead Consultants

Table 1.2 Summary of capital Cost Estimates

Table 2.1 Proposed Land-use

Table 2.2 Assumed Land-use for Battersea power station and 2-way trips (daily)

Table 2.3 Assumed Land-use for Nine Elms Corridor and 2-way trips (excluding BPS)

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Table 2.4 Battersea Station Peak Flows - Option 1

Table 2.5 Battersea / Nine Elms Stations Peak Hour Flows - Option 2

Table 2.6 Battersea / Vauxhall Stations Peak Hour flows - Option 3

Table 2.7 Split between Northern and Victoria Lines (Census 2001)

Table 2.8 Victoria Line Interchange at Vauxhall Peak Hour

Table 4.1 Kennington To Battersea Runtime

Table 4.2 Battersea to Kennington Runtime

Table 4.3 Kennington To Battersea via Nine Elms Runtime

Table 4.4 Battersea to Kennington Via Nine Elms Runtime

Table 4.5 Kennington To Battersea Via Vauxhall Runtime

Table 4.6 Battersea to Kennington Via Vauxhall Runtime

Table 4.7 Battersea Terminus Layover

Table 4.8 Kennington / Battersea Fleet Requirements

Table 4.9 Kennington / Nine Elms / Battersea Fleet Requirements

Table 4.10 Kennington / Vauxhall / Battersea Fleet Requirements

Table 5.1 Summary of Cost Estimates

APPENDICES

A RESIDUAL ISSUES REGISTER

B BATTERSEA STATION AND CROSSOVER WORKING ASSUMPTION

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1. INTRODUCTION AND SUMMARY

Summary

1.1 The Greater London Authority (GLA) is currently developing an Opportunity Area Planning Framework (OAPF) for Vauxhall / Nine Elms and North East Battersea (VNEB) in order to deliver a comprehensive framework for the development of the OA. The Battersea Power Station (BPS) site is located within the VNEB OA. The VNEB OA is illustrated in Figure 1.1. The draft OAPF is expected to be complete by March 2009.

1.2 The VNEB OA is in the Central Activities Zone (CAZ). The CAZ contains a cluster of vitally important activities such as financial and business services sector, retail, tourism, media and government offices. The London Plan seeks to ensure that the diverse, dynamic and innovative nature of the area is built on.

1.3 Policy 5G.2 states that the Mayor and boroughs will ‘identify and bring forward capacity through redevelopment within appropriate quarters of the CAZ, through development and redevelopment in Opportunity and Intensification Areas.’

1.4 BPS is a key regeneration site located in the north west corner of the OA. Much of the OA suffers from poor public transport accessibility and weak linkages to the surrounding area.

1.5 Excellent transport links are key to the success of the CAZ, with improved public transport capacity therefore fundamental to accommodating growth in the OA, which is why rapid transit type solutions are being considered for the OAPF.

1.6 A number of development scenarios using the baselines set out in the London Plan Consolidated (2008) have been developed. These are being used by the OAPF team to test development capacity in the Opportunity Area and on the inner and central London transport network as a whole and the level of transport intervention required to support each. The scenarios are as follows:

• Scenario 1 – Low density residential - 8,000 jobs and 4,200 homes

• Scenario 2 – Medium density residential - 8,000 jobs and 8,500 homes

• Scenario 3 – High density residential - 8,000 jobs and 16,000 homes

• Scenario 4 - High density residential + retail destination - 12,000 jobs and 16,750 homes

• Scenario 5 – High density residential + retail + office destination - 27,000 jobs and 16,750 homes

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FIGURE 1.1 VAUXHALL/NORTH EAST BATTERSEA (VNEB) OPPORTUNITY AREA

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1.7 The large-scale development of the Battersea Power Station site proposed by Treasury Holdings Ltd (THL) and the more extensive land use scenarios with high levels of development in the VNEB OA can be achieved only if there is a step change in public transport accessibility and capacity.

1.8 As part of Steer Davies Gleave’s (SDG) work for THL, SDG developed tram and tube options to serve the OA. The SDG report ‘Outline Feasibility Studies and Business Cases for Tram and Tube Options’ (February 2008) reviewed tram and tube options to serve the area.

1.9 This study concluded that an extension of the Northern Line (Charing Cross Branch) from Kennington to Battersea Power Station is the only practical means of providing the required level of public transport accessibility to support both the proposed level of development of the BPS site and high levels of development in the OA.

1.10 As part of the necessary preparation in advance of a proposed Transport and Works Act Order (TWAO) submission in 2010, THL commissioned the following team of specialist consultants jointly to prepare a preliminary feasibility study and business case to assess the three tube extension options.

TABLE 1.1 WORK AREAS/LEAD CONSULTANTS

Work Area Lead Consultant

Programme Management Steer Davies Gleave (SDG)

Engineering Feasibility / Station Architecture Parsons Brinckerhoff (PB)

Business Case Steer Davies Gleave (SDG)

Transport Planning / Rail Operations Steer Davies Gleave (SDG)

Environmental Assessment URS Corporation Ltd (URS)

Planning DP9 Planning Consultants (DP9)

1.11 SDG has provided Programme Management services to support the development of the preliminary feasibility study and business case. The SDG Programme Management team have been responsible for facilitating the interfaces and the coordination of activities across all the consultant teams.

1.12 London Underground Limited (LUL) has also provided engineering and operational planning support to the consultant team through representatives from LU’s Engineering and Strategy & Service Development directorates. Atkins and Bircham Dyson Bell are also advising the team on engineering and legal/TWAO aspects respectively.

1.13 The feasibility study and business case work considered three route options for the extension:

1. Direct to Battersea Power Station

2. To Battersea Power Station via a new station in the Nine Elms area

3. To Battersea Power Station via a new interchange station at Vauxhall

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1.14 The three tube alignment options are illustrated in Figure 1.2.

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FIGURE 1.2 NORTHERN LINE EXTENSION OPTIONS

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1.15 This Final Report forms the third deliverable of the overall programme of works following issue of the Inception and Interim Reports in July and October 2008 respectively.

1.16 This report should be read in conjunction with both the Parsons Brinckerhoff Feasibility Report, December 2008 (PB Ref UMD90388A/0039/03) and the URS Preliminary Environmental Assessment Final Report, Issue 5, December 2008 (URS Ref: 49315981).

Business Case

1.17 It should be noted that the preliminary business case (Section 7) has yet to be completed as this is dependent on modelling and forecasting work commissioned by TfL from SKM as part of the development of the Opportunity Area Planning Framework. Results from this modelling are required as inputs to the business case appraisal for the tube extension. Significant delays to the programme for this modelling work now mean that final outputs are not expected from SKM until January 2009. The business case will then be completed in February/March 2009 and a separate SDG report will be issued covering the Business Case.

1.18 This business case will be prepared for the high density development scenario (27,000 jobs and 16,750 homes) which is the most consistent (in terms of order of magnitude) with the current development proposals at BPS.

Feasibility Study

1.19 The feasibility study undertaken by Parsons Brinckerhoff was structured in three phases, which sought, in turn to: identify critical design issues leading to possible variants of each option; narrow down a list of possible variants, ideally to a working assumption for each route option; and finally to develop the working assumption sufficiently to undertake the preliminary feasibility study and business case.

1.20 In practice, various alternative options remain, which have been neither ruled-out completely, nor adopted as the basis for completing the preliminary feasibility study. These options could lead to a final specification with lower cost and risk and should therefore be revisited at the next stage of scheme development. These issues are included as part of the “next steps” identified in the final chapter of this report.

1.21 The feasibility study concluded that the extension is feasible. It identified a range of critical issues with ensuing possible design variants but no insuperable obstacles. These issues are:

• Battersea Station and Cross-Over Configuration: The sensitive Thames Water ring main constrains the site for the station and crossover to the east. A wide range of possible options (9 distinct configurations) have been considered for the purposes of fitting both the station and crossover within the site as discussed in section 3.7. The option that has been developed as a working assumption has the crossover to the east of an island platform with platform edges curving in towards the crossover. Both station and crossover are proposed to be constructed within a box excavation. The

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current crossover is a relatively long arrangement to maximise train speed and this requires the onward running tunnels to be of enlarged diameter as they enter the box. Whilst the adequate operational performance of this option remains to be demonstrated, LUL have indicated that with a well managed stepping back operation 28tph should be achievable. Possible opportunities to shorten the length of the crossover and maximise the operational capacity should be reviewed at the next stage of design whilst ensuring adequate reversing capacity.

• Connections at Kennington: Various possibilities have been considered for connecting with the existing tunnels at Kennington, including junctions to both the inside and outside of the turn-around loop and with the cross-over tunnels between the Charing Cross and City branches. The latter option was not adopted (but not ruled out) because of the short length of those tunnels, which meant that the level of detailed investigation and design required to demonstrate feasibility would be impractical in a preliminary feasibility study. Connections to the inside of the loop posed difficulties in aligning and constructing the tunnels on approach. The option adopted for completing the preliminary feasibility study is therefore step-plate junctions to the outside of the straight sections at the root of the turn-around loop. These would be constructed around the existing tunnels, requiring only a series of short possessions to break in and install the turnouts. It is thought that some track realignment and removal of cant will be required in the adjacent running tunnels, which could be undertaken during normal engineering hours.

• Location of “Nine Elms” Station (Route Option 2 only): Several possible sites have been identified, including the existing Sainsbury’s supermarket car park site on Wandsworth Road, the Travis Perkins builders’ merchants’ yard to the east of that and on the corners of both the Flower Market and New Covent Garden Market. Alignments appear to be achievable to reach each of these locations and to retain planning flexibility, therefore, none of these locations have been firmly ruled out at this stage. A station location at the Sainsbury’s site (on land owned by New Covent Garden and Sainsbury’s) has been used as a working assumption, however, and the feasibility study was taken forward on that basis.

• Potential Provision of Integrated Station at Vauxhall (Route Option 3 only): A wide range of significant obstacles have been noted in relation to the implementation of the interchange station at Vauxhall which defines Route Option 3. These relate to many factors including engineering feasibility, ground conditions, compliance with standards, cost, operations and transport planning. A possible configuration at Vauxhall station has been developed and costed. The working assumption is a new station located immediately to the south of the existing station and consists of basement-level mined station tunnels linking to the existing Victoria Line ticket hall, which would be expanded and improved.

• Alignments: Alignments have been established for all three route options. In some cases it would be optimal to tunnel under the Oval cricket ground near Kennington and avoiding the Oval would introduce sub-standard curvature to the track. Although this would not be severe enough to contravene standards, the increased lifetime maintenance costs must be considered due to wheel/train interface between train and track. Therefore, the working assumption is for alignments under the Oval where this

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is optimal for the route. Feasible horizontal and vertical alignments are presented in the Parsons Brinckerhoff Feasibility Report.

• Train operations and Capacity of Battersea as Terminus: The incorporation of an extension to Battersea into likely future service patterns for the Northern Line has been considered. As a result, it is not thought that the extension to Battersea is dependent on any aspect of the possible future developments of the service pattern. With no trains being timetabled to turn at Kennington, the need to turn around the 28 trains per hour associated with the proposed “Northern Line Separation” at Battersea is a key point of specification for the scheme, as is keeping the Kennington Loop operational for emergencies and service recovery.

Environmental Constraints

1.22 A Preliminary Environmental Assessment has been undertaken by URS which has identified and mapped the key environmental considerations throughout the implementation and operation of this proposed scheme and to undertake a preliminary Environmental Assessment of anticipated environmental and socio-economic impacts of the route options.

1.23 Given that this is an underground scheme, other than geological constraints, these are thought to be mostly relevant to the temporary and permanent surface structures such as stations, access shafts and construction access. Consideration has also been given to the environmental impacts of construction (and spoil removal in particular). As with the engineering feasibility study, no “showstoppers” have been identified to date.

1.24 However, the location of construction access shafts and permanent ventilation/intervention shafts has been identified as a critical issue in terms of approvability on environmental grounds. It is expected that optimal locations of shaft heads, in terms of environmental and engineering impact, should be considered in detail at the outset of the next stage of scheme development. Alignments might have to be adjusted to accommodate these. This will need to be discussed with the LFEPA.

1.25 The impacts associated with operational noise and vibration during operations is also expected to be a key issue and further study will be required, as well as likely physical mitigation measures.

1.26 In summary, the Preliminary Environmental Assessment, has concluded that Option 2 (via a new station in Nine Elms) is the least environmentally sensitive option, and Option 3 (via Vauxhall) is the most environmentally sensitive option.

Risk Management

1.27 An initial risk register was established at inception and has since been reviewed. An in-depth risk workshop was held on Thursday 18th September 2008, which was attended by THL, representatives from the consulting team, including URS, SDG, PB (and its subcontractors) and representatives of LUL.

1.28 A second risk workshop was then held on 10th October 2008, with the same group but a wider attendance from LUL. This workshop took account of the feasibility study’s initial conclusions on working assumptions, including horizontal and vertical alignments and

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station arrangements. The risk register was further developed to incorporate the results of this workshop.

1.29 The current programme has detailed feasibility study and business case appraisal during 2009 with a TWAO application in early 2010, a public inquiry in late 2010, construction from 2012 to 2015 and earliest possible train/passenger operations from mid 2015.

Cost Estimates

1.30 Cost estimates have been prepared by Corderoy for PB, for each of the three route options to a confidence level of ± 30% for Routes 1 & 2 and ±40% for Route 3. Cost estimates are detailed in section 5 of this report and are summarised below:

TABLE 1.2 SUMMARY OF CAPITAL COST ESTIMATES

£m

Route 1 – Kennington – Battersea direct 426

Route 2 – Via Nine Elms 506

Route 3 – Via Vauxhall 680

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Transport Improvements

1.31 The anticipated improvement in public transport accessibility levels (PTAL) as a result of the proposed extension of the Northern Line is illustrated by the PTALs in Figures 1.3 (existing) and 1.4 (with Northern Line, Option 2 extension) below.

FIGURE 1.3 EXISTING PTAL

FIGURE 1.4 PTAL WITH TUBE EXTENSION TO BATTERSEA & NINE ELMS (OPTION 2 SHOWN)

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1.32 Figures 1.3 and 1.4 show how the tube station will dramatically improve the PTAL particularly in the central and western parts of the OAPF. High PTALS will support the scale of development proposed by THL and the high density scenarios being considered by the OAPF.

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2. PATRONAGE FORECASTS

Proposed Approach to Patronage Forecasting

2.1 SKM has been commissioned by TfL, (jointly funded by THL and Ballymore) to undertake modelling work in support of the Nine Elms OAPF.

2.2 This work is being undertaken using a modelling suite comprising the LTS Model, a Railplan model of public transport and a Saturn highway model.

2.3 Forecasts are being undertaken for 5 different demand growth scenarios, based on different development assumptions for the Nine Elms corridor. The modelling of Scenario 5, with the highest level of assumed development, will be undertaken separately with each of the three proposed options for a Northern Line tube extension from Kennington to Battersea Power Station represented. Steer Davies Gleave is liaising with SKM on the specification of these model runs.

2.4 It has been agreed with SKM that a “Reference Case” do-minimum scenario will also be modelled for comparison, which excludes the extension of the Northern Line to Battersea while still incorporating the Scenario 5 development assumptions, but does include a reasonable assumption as to the development of existing transport modes in the light of this demand growth. (i.e. increased frequency and capacity of local bus services).

2.5 The format of outputs from these model runs has been agreed with SKM and it is envisaged that these will include (in addition to material needed for the business case appraisal):

• Tube station entry/exit/interchange matrices for the modelled periods;

• Link flow reports for the tube network (difference with and without tube extension) and the Northern and Victoria Lines in particular; and

• Difference plots of the demand impact across the wider network

2.6 This will be reviewed and critiqued by Steer Davies Gleave’s transport planners before being presented in graphical and tabular form.

2.7 Using appropriate annualisation factors, overall forecast impacts on annual bus and tube patronage will be derived.

2.8 In advance of the results from the SKM modeling, SDG has developed preliminary station demand estimates to inform PB’s initial spatial layout planning for the various station options. AM/PM peak hour demand estimates have been developed for the following:

• Battersea station entry/exit flows (all 3 tube options)

• Nine Elms station (for option 2)

• Vauxhall (Northern Line) interchange flows (for option 3)

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Trip Generation for Battersea Power Station & Nine Elms Corridor

2.9 For the purpose of this initial trip generation exercise, the high density scenario 5 (27,000 jobs and 16,750 homes) has been considered to reflect the size of the proposed development on the BPS site. The development would comprise high density residential and also retail and office destination development.

2.10 Table 2.1 describes the land-use that has been assumed for each for the purpose of this assessment. Nine Elms corridor would be a mix of mainly residential and office, whilst the BPS development would be more of a mixed use development with leisure, hotel, large retail, office and also few residential units.

TABLE 2.1 PROPOSED LAND-USE

Battersea Power

Station Nine Elms Corridor Total Option 5

Employment (jobs) 17,000 10,000 27,000

Visitors (people per day)

45,600 - 45,600

Residential units 3,000 13,750 16,750

2.11 The BPS development is assumed to be more mixed use, so each land-use has been further broken down into type of employment to indicate the impact that this would have on the daily profile for trips and the peaks.

2.12 TRAVL has been used to obtain trip rates for each type of Land-use and daily profiles.

TABLE 2.2 ASSUMED LAND-USE FOR BATTERSEA POWER STATION AND 2-WAY TRIPS (DAILY)

Land-use Units Employment Visitors Total

(2-way trips)

Leisure 450 2,250 5,400

Cultural 380 2,500 5,760

Office 12,600 1,070 23,560 *

Hotel 500 400 600 3,000

Retail 3,150 38,000 44,300 **

Residential 3,000 18,000

Totals (Rounded) - 17,000 44,500 100,000

* Assuming 85% staff occupancy for offices. It is assumed that other land-uses have 100% staff occupancy.

** Assuming 50% reduction in Retail visitors from 37,981 due to chain trips.

2.13 The rest of the Nine Elms corridor on the contrary would be mix of mainly residential units with some offices. Table 2.3 shows the land-use for Nine Elms corridor and total 2-way

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trips that it would be assumed to generate.

TABLE 2.3 ASSUMED LAND-USE FOR NINE ELMS CORRIDOR AND 2-WAY TRIPS (EXCLUDING BPS)

Land-use Units

Employment Visitors Total

(2-way trips)

Residential 13,750 - - 82,500

Office - 10,000 - 17,000

Totals 13,750 10,000 - 99,500

Background Trips

2.14 With the introduction of the tube, it is likely that there would be a change in the existing mode share for the wards that are in vicinity of the BPS development, thus generating additional demand for the proposed tube stations in addition to that generated by the development proposals.

2.15 It has been assumed that there would be a shift from bus, car and rail modes. This would result in 17,000 additional 2-way trips. Equating to 2,500 total additional trips in and out of the station at Battersea both in the AM and PM peak hours.

2.16 However for the option with intermediate station at Nine Elms, the wards in the catchment already have access to other Northern Line stations – Oval, Stockwell and Vauxhall. Hence a new station might not have a significant impact on existing mode share. However, the shorter walk times / proximity to the new station at Nine Elms would make the new station more attractive for existing tube users and bus passengers.

2.17 This would result in an additional demand of 5,000 passengers at Nine Elms station in addition to those from the new development. This would equate to 1,000 total additional trips in and out of Nine Elms station both in the AM and PM peak hours. The same number of additional trips would be included in Vauxhall demand in option 3.

Initial Patronage Estimation (to inform Design Parameters)

2.18 The following station demand forecasts are based on an estimated tube mode share of 39% assumed in the initial SDG Outline Business Case (February 2008),

2.19 The estimated distribution of trips between Battersea, Nine Elms and Vauxhall stations has been based on an initial assessment of the likely catchment area for each station and has assumed the following:

• Option 1 – Assumed that Battersea station would attract 95% of BPS development tube trips and 65% of tube trips from Nine Elms corridor.

• Option 2 – Assumed that Battersea station would also attract 95% of BPS development tube trips but only 35% of tube trips from Nine Elms corridor. 45% of

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Nine Elms corridor tube trips would instead use Nine Elms station with another 20% assumed to use the existing station at Vauxhall because of proximity to the station. This would also include passengers that would use the bus to get to Vauxhall even if there was a Northern line connection at Vauxhall.

• Option 3 – Assumed that Battersea Power Station would attract 100% of BPS development tube trips and 50% of Nine Elms corridor tube trips. It is assumed that 30% of Nine Elms corridor tube trips would instead use the Northern Line connection at Vauxhall station i.e. the majority of trips that would have used Nine Elms station in option2.

2.20 Tables 2.4, 2.5 and 2.6 summarise these preliminary peak hour station demand forecasts for each of the three stations. These are very high-level estimates based only on assumed trip-making from proposed new development and benchmarking of other sources of demand. The distribution between the three Battersea station entrances is notional at this stage.

2.21 These demand forecasts relate to no specific forecast year and are designed only as a reasonable basis for initial architectural planning of tube stations. They should not be used uncritically for any other purpose. More detailed outputs will be provided to the engineering and architectural team following the completion of SKM’s OAPF modelling exercise.

Option 1: Extension from Kennington to a new statio n at Battersea

2.22 Estimated Battersea station peak hour demand is shown in Table 2.4.

TABLE 2.4 BATTERSEA STATION PEAK FLOWS - OPTION 1

In Out Total flows

Battersea Station

AM Peak 5,600 4,200 9,800

PM Peak 4,700 4,700 9,400

Option 2: Extension from Kennington to a new statio n at Battersea via an intermediate station at Nine Elms

2.23 Estimated Battersea and Nine Elms station peak hour demand is shown in Table 2.5.

TABLE 2.5 BATTERSEA / NINE ELMS STATIONS PEAK HOUR FLOWS - OPTION 2

In Out Total Flows

Battersea Station

AM Peak 5,000 3,700 8,700

PM Peak 5,600 2,800 8,400

Nine Elms Station

AM Peak 3,700 1,700 5,400

PM Peak 3,700 1,500 5,200

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Option 3: Extension from Kennington to a new statio n at Battersea via a connection at Vauxhall

2.24 Estimated Battersea and Vauxhall Northern Line peak hour demand is shown in Table 2.6.

TABLE 2.6 BATTERSEA / VAUXHALL STATIONS PEAK HOUR FLOWS - OPTION 3

In Out Total Flows

Battersea Power Station

AM Peak 5,400 4,100 9,500

PM Peak 6,000 3,000 9,000

Vauxhall Northern Line Platforms

AM Peak 3,400 1,500 4,900

PM Peak 3,400 1,300 4,700

Interchange at Vauxhall

2.25 Option 3 would provide interchange between the Victoria Line and the Northern line at Vauxhall. In order to estimate potential interchange demand, existing journey to work trips from four wards have been considered along the Northern Line just south of the development.

2.26 From existing journey to work census data for the four wards, it can be assumed that about 40-45% of total tube work trips were more likely to be on the Victoria Line and the rest on the Northern Line, providing an indication of where people living in those wards work. It has therefore been assumed that approximately 40% of Battersea station trips would interchange to the Victoria line at Vauxhall.

TABLE 2.7 SPLIT BETWEEN NORTHERN AND VICTORIA LINES (CENSUS 2001)

Line Ward 1

Ward 2

Ward 3

Ward 4

Northern Line 52% 63% 62% 61%

Victoria line 48% 37% 38% 39%

TABLE 2.8 VICTORIA LINE INTERCHANGE AT VAUXHALL PEAK HOUR

In Out Total Flows

Vauxhall Victoria Line Platforms

AM peak 1,300 600 1,900

PM peak 1,300 500 1,800

2.27 All initial patronage forecasts will be reviewed when the OAPF modelling is complete.

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3. SCHEME DEVELOPMENT

3.1 The technical feasibility study was divided into three phases. Phase 1 sought to identify key issues and challenges in terms of developing working assumptions for the three route options. It also identified possible variants in design and specification that could be pursued in relation to these issues. Phase 2 sought to evaluate these possible variants and, where possible, short-list them in moving towards a preferred working assumption for each of the route options which could then be taken forward to preliminary feasibility and finalised during Phase 3.

3.2 At the end of Phase 1, a workshop day was held (July 30th 2008) to address each of the key issues identified during Phase 1, clarify design variants that might be possible in relation to the issues, where possible eliminate variants, and finally to define the next steps for the engineering team (and others) towards reaching a preferred working assumption during the remainder of Phases 2 and 3.

3.3 Work to develop and then narrow down the design variants clarified in the workshop day was progressed by PB with input from LUL through regular Design and Engineering workshops.

3.4 The remainder of this chapter serves to record in summary the design variants considered in relation to the most notable feasibility issues arising.

Battersea Station and Cross-Over Configuration

3.5 The proposed location of a station box within the Battersea Power Station site and development masterplan is on the south-western corner of the site next to Battersea Park Road. The Thames Water Ring Main crosses the south-east corner of the site with an invert level of approximately -26m and a 2.76m diameter. A tunnel invert of approximately -16m is proposed for the Northern Line tunnels. It is considered highly unlikely that Thames Water would allow the excavation of a deep box over the Ring Main. Therefore the length available for the box construction is only about 200m. Within these constraints it will be necessary to construct both the station box and cross-overs.

3.6 LUL have specified various key requirements for the Battersea Station layout including 2 banks of 3 escalators (to allow sufficient capacity for scheduled and unplanned maintenance) which drives an increase in platform width to 17m, which in turn has an effect on the switches and crossings arrangements that push the layout even further towards Thames Water main.

3.7 In order to accommodate this, the following configurations have been considered, employing various combinations of boxed, mined cavern and bored tunnel construction:

Option 1 - Island platform. Crossovers to the west of the platforms (mined cavern outside BPS land boundary).

Option 2 - Island platform to the west of the box. Crossovers to the east of the platforms in a mined cavern above the ring main.

Option 3 - Side platforms. Crossovers to the east of the platforms within the box. Running lines outside the box possibly in a single cavern until separation allows twin bores.

Option 4 - As option iii but with the platform and crossover locations reversed.

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Option 5 - Side platforms towards the west of the site. Crossovers to the west of the platforms in a mined cavern outside the BPS land boundary.

Option 6 - Island platform towards the west of the site. Crossovers to the west of the platforms in a mined cavern (further) outside the BPS land boundary.

Option 7 - Partly curved island platform. Crossovers close to the east of the platforms, partly in a mined cavern over the ring main.

Option 8 - Fully curved island platform. Crossovers even closer to the east of the platforms very slightly in a mined cavern close to the ring main.

Option 9 - Straight-edged triangular island platform. Crossovers immediately to the east of the platform within the box.

3.8 Cost estimates for the 9 different combinations of station layout/position and crossover layout/position (as set out in paragraph 3.7) have been produced by Parsons Brinckerhoff which indicate only minor differences in cost for the various options, therefore the decision for the preferred working assumption was based only on engineering feasibility.

3.9 Considering the short length available from the western site boundary and the Thames Water Ring Main consultation zone, Options 3, 4 and 5 that involve side platforms were not preferred because these do not allow the tracks to diverge sufficiently to allow single track twin bored tunnelling to start at the end of the station/crossover box. Also, the side platforms are not ideal for passenger access because the number of access/egress points is doubled making access between platforms more complicated.

3.10 Options 1 and 6 were rejected because the crossover would be constructed in mined tunnel under Network Rail tracks and viaducts with associated settlement impacts and their mitigation expected to be significant. Construction access and methodology would also be more difficult.

3.11 Option 2 and 7 considered the construction of the crossover over the Thames Water ring Main, which is considered highly unlikely to be acceptable to Thames Water.

3.12 Whilst Option 9 gives the LUL ideal straight platforms, it would preclude the future extension of the over-run tunnels (avoiding the gas holders) if the line were to be extended to the west. The wedge shape is also not ideal for the design of the box.

Specification adopted for preliminary feasibility study

3.13 The option adopted in the Preliminary Feasibility Study as a working assumption for the Battersea station and crossover configuration is therefore Option 8 (PB drawing 90388A-GGP-10-016-1C is reproduced in Appendix 2); specifically, a single island platform, tapered towards crossovers at the east end of the platforms, all within a box construction. This specification involves an initial length of the running tunnels to the east of the box being bored at a slightly enlarged diameter in order to incorporate the end of the cross-over turnouts with the box construction not encroaching into the no-pile zone for the Thames Water Ring Main. All of LUL’s key requirements (see paragraph 3.6) are achieved with Option 8.

3.14 The platforms will be 118.5 metres long (as agreed with LUL) and are assumed to be curved (at 1500m radius) for 60 % of their length, with the remainder on straight track. The

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requirement to safeguard the possibility of extending the alignment further west in the future, avoiding the gas holders to the west of the site, has contributed to the choice of this design.

3.15 The design of the station and containing box has been specified to allow for the development of an 8 storey over-station development, the design of which would have to be approved by LUL.

3.16 The working assumption Battersea station layout assumes two entrances/exits directly off Battersea Park Road. The entrances extend to the rear of the station where a bank of three escalators leads to the ticket hall at level -6m. This arrangement allows for a potential connection between the ticket hall and the development on the unpaid side. Two banks of three escalators then connect to platform at -14m.

3.17 Coordinating design between the station and the Battersea Power Station masterplan will be very important during the subsequent stages of design, particularly the connection between the ticket hall and development entrance, the station box shape and the structural grid for the over-station development.

3.18 It remains to be conclusively demonstrated that this arrangement will allow the turning of up to 28 trains per hour at the station as a temporary terminus. An initial capacity assessment has been undertaken and reported in Chapter 4 but full simulation would only be practical during the next stage of design. However, LUL has indicated that, with a well managed stepping back operation, 28tph should be achievable and that a shorter length cross-over design might actually improve operational efficiency. This could potentially lead to a significant reduction in construction cost and should therefore be considered further during the detailed feasibility study.

Connections at Kennington

3.19 It is proposed to extend the Charing Cross branch of the Northern Line, which effectively terminates at Kennington in a run-around loop tunnel - although trains can continue southwards towards Morden by crossing at this point into the other branch.

3.20 Trains that currently reverse from Southbound to Northbound at Kennington using the run-around loop tunnel would instead continue on to Battersea Power Station via the new extension.

3.21 Ideally, a straight section of tunnel with un-canted track is required in order to construct a step-plate junction with the existing tunnel. With much initial uncertainty about the existing tunnel and track geometry, three potential options were identified, which are illustrated schematically in Figure 3.1:

• “Option 1a” Connections to/from the outside of the turnaround loop, at its roots;

• “Option 1b” Connections to/from the inside of the turnaround loop, at its roots; and

• “Option 2” Connections to/from the link tunnels between City and Charing Cross lines.

3.22 Option 1b (connection to the inside of the loop) was ruled out due to constraints on tunnelling the approaches to the junctions in the vicinity of existing tunnels.

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3.23 Option 2 was not adopted for the preliminary feasibility study because of the short length of the tunnels between Charing Cross and City branches. It was concluded that the short length of tunnel available introduced too great a level of uncertainty as to whether the connection could be fitted in, which could not be resolved with the level of investigation and design reasonably associated with a preliminary feasibility study. However, this option has not been conclusively ruled out and has been identified for possible further study at the next stage of scheme development. It is thought to have the potential to reduce costs by connecting to a section of running tunnel which could more reasonably be closed during excavation and construction.

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FIGURE 3.1 OPTIONS FOR LOCATION OF CONNECTION AT KENNINGTON

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3.24 The method of connection to existing tunnels at Kennington, adopted as a working assumption for the preliminary feasibility study, is Option 1a: Step plate junctions to the outside of the turnaround loop, close to its root within a straight section of the existing alignment.

3.25 It is intended that these step-plate junctions can be constructed around the existing tunnels with a series of possessions then being required to break into the existing tunnels and install turnouts. It has been identified that the existing straight sections of track are currently canted but it is believed that this cant could be removed and the track accordingly re-aligned during normal engineering hours prior to the main possession subject to safety considerations.

3.26 A great deal of cost and risk is associated with this part of the scheme and, although a particular approach has been adopted and shown to be feasible, it has been suggested that further scheme development work should again review alternative options that were not ruled out entirely, so as to ensure that the optimal solution is taken forward.

Location and configuration of New “Nine Elms” Stati on

3.27 Five possible sites have been identified for a potential station at Nine Elms as shown in Figure 3.2.

FIGURE 3.2 POTENTIAL NINE ELMS STATION LOCATIONS

• Site 1 - Beneath open space at the north eastern end of the New Covent Garden Market site, south of the mainline railway.

• Site 2 - Beneath open space towards the southern side of the Flower Market site, north of the mainline railway.

• Site 3 - At the existing Travis Perkins builders’ merchants’ yard (to the east of the Sainsbury’s site)

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• Site 4 - At the existing Sainsbury’s supermarket site immediately south of the mainline railway on Wandsworth Road.

• Site 5 - To the south side of the existing Sainsbury’s supermarket site, on land owned by New Covent Garden Markets and Sainsbury’s (car park).


3.28 For the purposes of developing this preliminary feasibility study, the land owned by New Covent Garden Market and Sainsbury’s car park to the south of the Sainsbury’s supermarket (site 5) is being taken as a working assumption as to the site of the Nine Elms station. It is understood that both Sainsbury’s and New Covent Garden Markets are keen to develop this land and initial discussions have been had with NCGM. This location also provides arguably the most convenient alignment and construction access and good potential links with buses in Wandsworth Road as well as the most substantial catchments and convenient pedestrian linkages.

3.29 However, sensible alignments could equally allow for the location of this station anywhere on the Sainsbury’s site or even at the Travis Perkins site. For flexibility in planning, these locations will not been completely ruled out at this stage pending further discussions with the various freeholders.

3.30 The preferred Nine Elms station layout assumes a single entrance/exit directly from Wandsworth Road leading into a ground-level ticket hall and a bank of three escalators connecting to platform level at -18.5m.

Provision of Turn-back Facility at Nine Elms

3.31 LUL operations experts have expressed concerns about the implications for service recovery should a train fail on the proposed extension. Although a cross-over is provided at the Battersea terminus and the intention is to retain the Kennington loop as a turnaround facility, the possibility of introducing an additional turn-back at Nine Elms has also been proposed by LUL. This is thought to be feasible using a pair of mined step plate junctions with a connecting tunnel. This is included in the capital cost estimates as an optional line item.

3.32 The requirement for this facility remains uncertain, however. A detailed operational assessment, perhaps involving simulation modelling, will be required early in the next stages of scheme development to establish whether this facility represents good value for money in terms of delivering significant improvement in service robustness and recovery.

Interchange Station at Vauxhall

3.33 A new interchange station at Vauxhall is considered the most difficult to achieve. Several critical constraints are identified in the PB report. The avoidance of these constraints has suggested that, in practice only a very deep-level station with low-level interchange tunnels and a new, separate ticket concourse could conceivably be made to work. But this would still have many shortcomings and risks in terms of construction, availability of construction sites and operability.

3.34 Owing to the need to put in a tight curve to the southbound line from the Kennington Loop, the limited open space and the preference to avoid construction of large platform tunnels

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beneath the Network Rail tracks and station, the options are limited.

3.35 A deep-level mined station with platforms at -24m accessed via a basement-level interchange from the existing Victoria line ticket hall, or via a new ticket hall located in the basement of adjacent buildings immediately to the south of the station, are thought to be the only deliverable arrangements.


3.36 A configuration based on expanding and improving the existing Victoria Line ticket hall and a basement level interchange has been adopted as a working assumption for the Preliminary Feasibility Study.

3.37 Significant feasibility and deliverability issues have been identified and a range of notable risks associated with planning, construction, operation and costs. A more detailed study would be required to confirm with certainty the feasibility of any connection at Vauxhall.

3.38 Furthermore, LUL has raised concerns regarding the adverse impact that provision of an interchange at Vauxhall would have on the existing station congestion as well as the loading on the Victoria line itself and other stations further along the Victoria Line.

3.39 The October 2008 announcement that the American Embassy wishes to relocate to a site in Nine Elms adjacent to the proposed Vauxhall alignment is likely to introduce an additional constraint for the development of this option.

Tunnel Alignments

3.40 Preferred horizontal and vertical alignments for each route option are presented in PB’s Feasibility Report.

3.41 The most convenient alignments for the direct route and that via a Nine Elms station involve tunnelling under the Oval cricket ground. It is assumed that this will be possible but if it proves to be too great a delivery risk alternative alignments are possible by the introduction of curves with acceptable radii. However, the increased length and curvature of the route might increase the lifetime operating and maintenance costs significantly through train / wheel interface maintenance costs.

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Ventilation and Evacuation

3.42 A series of potential intervention shaft locations have been identified and adopted as working assumptions for the purpose of the preliminary feasibility study. However, it is not clear that they would be approvable in terms of their visual impact at surface level. The next stage of scheme development should consider the approvability of a range of shaft locations and it should be understood that the alignment might ultimately have to be revised to accommodate the most acceptable locations.

Route Option 1

3.43 The preliminary feasibility study adopted the following intervention shaft locations for the route direct to Battersea:

• The western edge of the Sainsbury’s site (close to the Nine Elms station location in Route Option 2) above the southbound line with a cross-passage to the northbound line;

• At Claylands Road and Meadow Road (requiring compulsory purchase of existing property) above the northbound line with a cross-passage to the southbound line at the point where these lines diverge to approach the Kennington loop separately.

• Derelict land adjacent to the gin distillery on Montford Place, above the northbound line as it approaches the Kennington loop; and

• The North East corner of Kennington Park, above the southbound line as it leaves the Kennington loop.

Route Option 2

3.44 The preliminary feasibility study adopted the following intervention shaft locations for the route to Battersea via a new station at Nine Elms, which itself replaces one of the shafts required in Route Option 1:

• On green space at Claylands Road, between and linked to both the northbound and southbound lines at the point where these lines diverge to approach the Kennington loop separately.


• The North East corner of Kennington Park, above the southbound line as it leaves the Kennington loop.

Route Option 3

3.45 The preliminary feasibility study adopted the following intervention shaft locations for the route to Battersea via a new station at Nine Elms, which itself replaces one of the shafts required in Route Option 1:

• On a site, currently a parking lot, immediately to the east of Ponton Road and immediately adjacent to the mainline railway, above the southbound line with a cross-passage to the northbound line;

• Incorporated into the design of the new station at Vauxhall, between the southbound

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and northbound lines.

• On derelict land to the east of Montford place, just north east of the gasworks at Oval, above the northbound line.

• On open land within the gasworks site at Oval, above the southbound line;


• The North East corner of Kennington Park , above the southbound line as it leaves the Kennington loop.

Summary Approach to Construction

3.46 The following is a summary of the proposed construction methodology prepared by PB:

Box Construction of Stations

3.47 The Battersea and Nine Elms stations would be essentially box constructions with some limited mined caverns at either end.

3.48 It is assumed that both stations will be built using a diaphragm wall construction technique, which consists of excavating a trench in sections keeping each section filled with an engineering fluid or slurry called bentonite in order to support the ground using hydraulic pressure against the trench walls.

3.49 After the excavation of one section is complete a steel reinforcement cage is located in the trench and concrete is pumped in one single operation to build the wall displacing the bentonite support. The slurry can be recollected and used for the next section using the same methodology.

3.50 Provisional lateral supports are needed during construction. However, after the excavation is finished a structural base will be constructed to support the base of the wall and the works inside the station box can begin from the bottom to the top of the box replacing the provisional props with permanent structural members.

Battersea Station and Crossover

3.51 The station box at Battersea station will have enough space for the station and the crossover and it would be independent; thus its construction can be undertaken at the same time as the main tunnel construction.

Nine Elms Station

3.52 In contrast, the Nine Elms station box would be shorter because it only needs space for the station; any crossings would be located in the excavated chambers mined before or after the construction of the station. If the final preferred alignment is Option 1, a ‘flat’ tunnel would be provided to allow for the potential construction of the station in the future.

Vauxhall

3.53 Vauxhall station is located inside the London clay area. It would have to be a deep mined construction using mechanical excavation methods and would be lined with sprayed concrete. For the construction of the ticket hall and to give access to the excavation works,

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surface works would be necessary.

3.54 There are many obstacles to the feasibility of this station in general and construction access possibilities remain uncertain at this stage.

Running Tunnels

3.55 The main running tunnels would be bored from the Battersea Power Station site with spoil removal from that location, probably taken off site by river transport.

3.56 In the western part of the construction site after the construction of the Battersea station box is finished, but before the construction of the station, two 70 metres over-run tunnels would be constructed using mechanical excavation methodologies and sprayed concrete.

3.57 Two additional 36 metres sprayed concrete tunnels will carry the tunnel boring machines from the eastern wall of the Battersea station box, over the TW Ring Main.

Kennington Connections

3.58 Two step plate junctions will be required for connection to the Kennington loop. For the construction of these junctions the guidance provided by LUL’s Manual of Good Practice G-55 would be used.

3.59 The chambers could be constructed using circular spheroidal graphite iron segmental linings except for the largest ones that will be constructed using elliptical lining. These have the advantage of reducing the volume of ground excavated and consequently the amount of settlement is also reduced.

3.60 The chambers will use the two permanent ventilation and intervention shafts closest to the Kennington loop as access points. To access the southern chamber a 160 metres tunnel will be required and to access the northern chamber an approximately 260 to 320 metres tunnel. These tunnels will be constructed using an open face tunnel boring machine and will arrive alongside the existing loop tunnel.

3.61 Construction of step plate junction requires a significant amount of hand mining especially for the excavation of the initial heading and chimney. There will be controls to ensure that workers are not exposed to the maximum limits of vibration. The design of the chamber will allow for the use of mechanical excavating equipment up to 1700 mm working width.

Summary Construction Programme

3.62 PB’s Preliminary Feasibility Report, includes estimated construction programmes relating to the adopted specifications for each of Routes 1, 2 and 3. The top-level summaries for each of these are reproduced below, in Figures 3.2, 3.3 and 3.4.

3.63 Dependent on the programme for the proposed TWAO, construction for Routes 1 and 2 could start in 2012 and be completed by September 2015, but route 3 (via Vauxhall) would take 15 months longer (due to the construction of a new interchange station at Vauxhall) and would not be completed until December 2016.

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FIGURE 3.3 SUMMARY ESTIMATED CONSTRUCTION PROGRAMME: ROUTE OPTION 1

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4. TRAIN OPERATIONS

Existing Service Pattern

4.1 In order to reduce the problems and complexity of the Northern Line’s previous service pattern as a result of irregular headways, particularly during the peak periods, the current service pattern was introduced earlier this year. This is shown by Figure 4.1 for both the AM and PM peak. The new service pattern significantly separates the two lines in the AM peak with the majority of the Morden services operating via the City branch through Camden Town to Mill Hill and High Barnet. The Morden/Charing Cross branch service have been reduced from 10 to 6 in both peaks and these are integrated with the services commencing from Kennington through Camden to serve the Edgware branch only.

FIGURE 4.1 EXISTING NORTHERN LINE SERVICE PATTERN AM AND PM PEAK

4.2 The Morden branch is currently served by 28 trains in the AM and PM peak hours. This is achieved by through-running 22 trains per hour serving the Bank / City branch and 6 Charing Cross branch services. The remainder of the Charing Cross branch service terminates at Kennington and turn through the Kennington Loop to inter-work with the returning northbound Morden / Charing Cross services.

4.3 The current timetable has enabled a more consistent headway to be operated in the peaks improving the operability and reliability of the service.

4.4 The off peak frequency is reduced compared with the AM peak and provides more direct journeys, with the services on each central branch splitting at Camden to serve both the Edgware and the High Barnet routes. The Morden services operate via the City branch only. This is shown in Figure 4.2.

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FIGURE 4.2 EXISTING NORTHERN LINE SERVICE PATTERN OFF-PEAK

Tube Lines Service Improvement

4.5 The current PPP arrangement with Tube Lines requires a significant level of service improvement to be delivered by 2012. This will be achieved through the implementation of Thales Seltrac moving block signalling system to provide increased service frequencies and journey time improvements, providing greater capacity with the existing vehicles. The proposed service upgrade is shown in Figure 4.3.

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FIGURE 4.3 2012 PROPOSED SERVICE IMPROVEMENT WITH NEW SIGNALLING AM AND PM PEAK

4.6 The service improvements will see the peak service frequency increase to 32 trains per hour (from 28) on the Morden branch and to 24 per hour per direction on both the Charing Cross and City branches (from 22 now). On the Morden branch 24 trains per hour will run through to the City branch and 8 trains per hour will run through to the Charing Cross branch. This will result in 16 of the Charing Cross branch services terminating at Kennington and turning through the Kennington Loop to inter-work with the returning northbound Morden / Charing Cross services.

Proposed Partial Separation of the Northern Line

4.7 To provide additional capacity improvements LUL have developing initial proposals to partially separate the two branches of the Northern Line. This could result in a service pattern shown in Figure 4.4.

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FIGURE 4.4 PARTIAL SERPARATION OF THE NORTHERN LINE AM AND PM PEAK

4.8 The proposed arrangement would result in the Charing Cross branch services being separated from the through route to Morden with all the services terminating at Kennington utilising the Kennington Loop i.e. 28 trains per hour.

4.9 The extension of the Northern Line to BPS does not preclude or require the introduction of partial separation.

Runtimes

4.10 Runtimes for each of the route options have been developed utilising a spreadsheet based runtime model adjusted to reflect the performance data for the Northern Line Tube stock, benchmarked against the performance achieved on existing sections of the Northern Line. The spreadsheet was also compared against the Jubilee Line extension where the quality of the infrastructure is similar to that proposed for the extension and where the resulting average train speeds are higher.

4.11 A reduced braking rate of approximately 0.7 m/s2 has been utilised for the trains entering the Battersea terminus based on the possible requirements for the Seltrac signalling system and an overrun tunnel length of approximately 50 metres. This resulted in an increased braking time of approximately 4 seconds.

4.12 The resulting runtime for the direct option from Kennington to Battersea is detailed in Table 4.1 westbound and Table 4.2 eastbound.

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TABLE 4.1 KENNINGTON TO BATTERSEA RUNTIME

Station Distance Time (min:sec) Average Speed

Kennington 0

Battersea 3.2 km 4:23

Total 3.2 Km 4:23 45 km/hr

TABLE 4.2 BATTERSEA TO KENNINGTON RUNTIME


Battersea 0

Kennington 3.1 km 4:10

Total 3.1 Km 4:10 45km /hr

4.13 The resulting runtime for the option from Kennington to Battersea via Nine Elms is detailed in Table 4.3 westbound and Table 4.4 eastbound. A dwell time of 25 seconds has been assumed at the intermediate stop.

TABLE 4.3 KENNINGTON TO BATTERSEA VIA NINE ELMS RUNTIME


Kennington 0

Nine Elms 2.3 km 3:05

Battersea 1.0 km 2:07 including dwell


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TABLE 4.4 BATTERSEA TO KENNINGTON VIA NINE ELMS RUNTIME


Battersea 0

Nine Elms 1.2 km 1:35

Kennington 2.1 km 3:27 including dwell


4.14 The resulting runtime for the option from Kennington to Battersea via Vauxhall is detailed in Table 4.5 westbound and Table 4.6 eastbound. A dwell time of 25 seconds has been assumed at the intermediate stop.

TABLE 4.5 KENNINGTON TO BATTERSEA VIA VAUXHALL RUNTIME


Kennington 0

Vauxhall 2.0 km 2:52

Battersea 1.5 km 2:35 including dwell

Total 3.5 Km 5:27 39 km /hr

TABLE 4.6 BATTERSEA TO KENNINGTON VIA VAUXHALL RUNTIME


Battersea 0

Vauxhall 1.6 km 1:59

Kennington 1.5 km 3:28 including dwell

Total 3.1 Km 5:27 40 km /hr

4.15 The resulting comparative westbound runtimes are:

• Battersea direct = 4:23

• Battersea via Nine Elms = 5:12

• Battersea via Vauxhall = 5:27

4.16 The resulting comparative eastbound runtimes are:

• Battersea direct = 4:10

• Battersea via Nine Elms = 5:02

• Battersea via Vauxhall = 5:27

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4.17 Runtime assessments for each of the route options will be undertaken in more detail at the next stage of design.

Capacity of Battersea Terminus

4.18 The capacity of a two track terminus arrangement and its ability to enable the termination and commencement of the return services at different service frequencies is a key criteria for the development of the Battersea station arrangement.

4.19 The service frequency terminating at Battersea will be the same as the peak frequency of the services proposed to terminate at Kennington with partial separation. These will up to 28 trains per hour depending on the timescales for both the extension and the proposed options to increase service frequency on the existing line.

4.20 Two platform arrangements are in use elsewhere on the London Underground network and are either operating at or proposed to operate at similar frequencies to those potentially required of the Battersea route. As the service frequency increases the layover time at Battersea needs to be reduced resulting in the need to step back drivers to allow drivers enough time to change ends.

4.21 Layover times have been developed for the different services frequencies based upon the runtimes into and out of the Battersea terminus, including the clearance time across the diamond crossing. The runtimes have been increased by 15% to provide for some variance in the runtimes. The departure time also includes an allowance for the inbound train to ensure the departing train is clear of the diamond crossing prior to the arrival of the inbound train needing to be impeded by the need to brake within the signalling braking distance.

4.22 The approximate layover time for the different service frequencies are shown in Table 4.7.

TABLE 4.7 BATTERSEA TERMINUS LAYOVER

Service Frequency Headway Layover

20 tph 3:00 4:20

24 tph 2:30 3:20

28 tph 2:00 (2:08) 2:20

Fleet Requirements

4.23 The additional fleet requirements for the proposed Battersea extension options have been developed for the existing and future service frequencies, and are shown in Table 4.8, 4.9 and 4.10.

4.24 The additional fleet requirements are based upon the developed runtimes for the different route options, the maximum layover permissible at Battersea for each service frequency minus an assumed current transit and layover time of 6 minutes at the current Kennington terminus. The current Kennington terminus Layover is based upon

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the extended dwell on arrival at Kennington, the transit time around the loop and the layover at Kennington prior to departure.

4.25 The identified fleet requirements do not allow for additional spares. It is assumed that the small number of additional trains can be maintained utilising the spare within the existing fleet.

TABLE 4.8 KENNINGTON / BATTERSEA FLEET REQUIREMENTS

20 Trains /Hr 24 Trains / Hr* 28 Trains / Hr**

Runtime K to B 4:23 4:23 4:23

Runtime B to K 4:10 4:10 4:10

Layover at Battersea 4:20 3:20 2:20

Minus Current Layover

6:00 6:00 6:00

Journey Time Increase

6:53 5:53 4:53

Additional Fleet Requirement

3 3 3

* PPP service increase ** Partial Separation

TABLE 4.9 KENNINGTON / NINE ELMS / BATTERSEA FLEET REQUIREMENTS


Runtime K to B 5:12 5:12 5:12

Runtime B to K 5:02 5:02 5:02



5:00 5:00 5:00


8:34 7:34 6:34


3 3 4


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TABLE 4.10 KENNINGTON / VAUXHALL / BATTERSEA FLEET REQUIREMENTS


Runtime K to B 5:27 5:27 5:27

Runtime B to K 5:27 5:27 5:27



5:00 5:00 5:00


9:14 8:14 7:14


4 4 4


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5. COST ESTIMATES

Capital Costs by Route Option

5.1 Costs estimates have been prepared by Corderoy for the three optimal route options developed by PB;

• Direct to Battersea Power Station

• To Battersea Power Station via a new station in the Nine Elms area

• To Battersea Power Station via a new interchange station at Vauxhall

5.2 These cost estimates are reported in Chapter 11 of PB’s Feasibility Report.

5.3 The following relevant information was available for the estimation of these costs:

• Indicative requirements for lifts (usage & loadings), escalators (numbers of, lengths), access, ventilation & intervention shafts (diameter’s & headworks), etc. for the M&E element.

• Construction programmes for each of the options such that preliminaries may be

estimated.

• A construction programme for the step plate junctions for which it is currently considered that the estimate will be resource driven rather than quantity driven.

• Dimensions for floors, columns, walls, etc.

• Indicative architectural requirements / finishes.

• Diameters of tunnels, particularly NATM / non bored elements.

• Anticipated ground conditions and ground treatment

5.4 In addition constraints imposed by third parties or assumed (Thames Water, LUL, Network Rail, etc.) have been considered along with identified risks and the resulting costs. This methodology will be subject to change as the design is developed in the next stage and additional information becomes available.

5.5 The capital costs for the options are summarised in Table 5.1. The cost estimates are £426m for Option1, £506m for Option 2 and £680m for Option 3.

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TABLE 5.1 SUMMARY OF COST ESTIMATES

Routes

1 2 3

£m £m £m

Battersea Station (including overrun) 109.5 109.5 109.5

Battersea Crossover Box 20.9 20.9 20.9

Nine Elms n/a 85.2 n/a

Vauxhall n/a n/a 230.0

Shafts 28.9 21.9 36.5

Tunnels 112.2 111.7 124.0

Step-plate junction 45.6 45.6 46.4

Linewide systems 58.3 60.5 61.0

Sub Total 375.4 455.3 628.3

Trains 36.0 36.0 36.0

Stabling 10.0 10.0 10.0

Nine Elms Crossover/Vauxhall 4.5 4.5 5.4

Total (Rounded) 426.0 506.0 680.0

5.6 Excluded from the estimates shown in Table 5.1 are:

• Cost incurred to date;

• Cost of LUL and Infraco team, Council and other Authorities including design and project management duties;

• Preparing, promoting and supporting any Transport and Works Act costs;

• Client costs developing the project design and during construction phase;

• Land costs;

• Operating, maintenance and renewal costs;

• Project risk or contingency;

• Compensation to LUL, Infracos or any other parties;

• Cost of upgrading the existing network to improve or maintain reliability;

• VAT, Taxes and Fluctuations, i.e. inflation;

• Main contractor’s design costs;

• Commissioning; and

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• Changes in legislation affecting the construction project

5.7 It should be noted that these exclusions may add 15%-20% to the base cost.

5.8 The estimates have been prepared on the basis that:-

• All construction work and E&M and system installations are encompassed in a fully designed single point contract. There will be an employer/Main Contractor agreement with the Main Contractor deemed to sub-contract as appropriate. It is likely that increasing interfacing by splitting the works into smaller contracts will increase cost by way of supervision and the risk of disruption.

• The duration of the contract and construction activities reflected in the estimate are as represented by the programme applicable to the various options.

Confidence level

5.9 The confidence level for Routes 1 & 2 is estimated as ± 30% and ±40% for Route 3.

Operating Costs

5.10 Initial Operating Costs estimates have been developed from information supplied by LUL and benchmarked against higher level information taken from TfL’s 2006/07 Annual Report, 2007/08 Accounts and the LUL Environmental Report 2005. The information supplied and extrapolated has been used in conjunction with the developed runtime and lengths of the route options to develop operating costs for the route options.

5.11 The following operating cost estimates are supported by a developed operating cost model which details all the costs, assumptions and sources of information. As a benchmark, an operating cost per kilometre of £13.81 has also been developed based on the total operating cost for 2007/08 excluding the PPP upgrades to provide a comparative benchmark for the resulting operating cost estimates.

5.12 The resulting comparative operating cost estimates (rounded) are:

• Battersea direct = £7.9m per year

• Battersea via Nine Elms = £9.8m per year

• Battersea via Vauxhall = £9.6m per year

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6. ENVIRONMENTAL IMPACTS AND CONSTRAINTS

6.1 This chapter summarises the Preliminary Environmental Assessment undertaken by URS Corporation Ltd (URS) for each of the three tube extension options. This chapter should be read in conjunction with the URS Preliminary Environmental Assessment Final Report, Issue 5, December 2008 (URS Ref: 49315981).

Overview of Key Environmental Considerations and Impacts

Construction Phase

6.2 The following technical aspects were thought to require further consideration within the construction phase Preliminary Environmental Assessment. A brief synopsis of each is provided below.

Noise & Vibration

• Potential noise and vibration from tunnel/shaft and station excavations/construction to local residents, the public, local businesses and services (e.g. hospitals and schools), listed buildings and amenity areas/open spaces; and

• Vibration impact on the Thames Water Ring Main and other underground utilities and assets.

Air Quality

• Airborne dust generation/nuisance to local residents, workers, and pedestrians from excavations, materials handling and concrete batching; and

• Emissions of Nitrogen oxides (NOx) and fine particulates/dust (PM10) from construction plant and traffic.

Socio-Economics

• Employment during construction phase; and

• Temporary loss of amenities/local facilities/open space.

Ground Conditions

• Disturbance/mobilisation of any sub-surface contaminants during excavation;

• Creation of new pathways for contaminants to enter surface and groundwater resources;

• Geo-hazards e.g. unexploded ordnance;

• Impact on ground and surface water abstractions;

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• Potential for the introduction of new sources of contamination e.g. from plant, equipment and construction materials;

• Disturbance of contaminated land and mobilisation of potential contaminants into groundwater/surface water resources; and

• Settlement/ground movement.

6.3 Whilst URS has considered broadly the potential impacts associated with geotechnical hazards and ground conditions, it should be noted that PB have undertaken a Geotechnical Desk Study of the Study Area. The Geotechnical Desk Study and resulting analysis of the geotechnical and engineering considerations is presented in Section 4 of the ‘Northern Line Extension to Battersea Power Station Engineering and Architectural Feasibility Study’, dated December 2008. This joint approach to the assessment of the ground conditions of the Study Area has enabled a preliminary assessment of the geotechnical hazards to be taken into consideration at the engineering and environmental feasibility stage.

Water Resources

• Increased suspended sediment loads in surface waters at points of spoil handling and stockpiling;

• Mobilisation of oils and fuels;

• Mobilisation of concrete and cement products;

• Disturbance of contaminated land and mobilisation of potential contaminants into groundwater/surface water resources;

• Disturbance of foul drainage; and

• The requirement for dewatering during excavation due to encountering water bearing sands, seepage from perched water tables and boring through the Lambeth Group.

Ecology

• Direct loss of, or damage to habitats and species during construction; and

• Indirect impact to habitats and species as a result of dust and noise generation during excavation/construction activities.

Waste Management

• Potential for contaminated excavated materials – soil classification prior to disposal of waste; and

• Spoil excavation and management.

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Archaeology & Built Heritage

• Impacts to archaeological resources; and

• Impacts to listed buildings – both direct (i.e. structural) and indirect (i.e. their setting).

Operational Phase

The following technical aspects were thought to require further consideration within the operational phase Preliminary Environmental Assessment. A brief synopsis of each is provided below.

Noise & Vibration

• Vibration and re-radiated noise from tube operations below ground;

• Noise from ventilation shafts; and

• Operational noise associated with use of the station e.g. tannoy systems and servicing traffic noise.

Air Quality

• Changes to the level of emissions by mode shift from use from private vehicles to use of underground services; and

• Potential for worsened localised air quality around permanent ventilation shafts.

Ground Conditions

• Long term settlement/ground movement – impact on built structures.

Water Resources

• Flood risk; and

• Potential for contamination from in-situ materials.

Socio-Economics

• Employment during the operational phase;

• Wider economic impacts;

• Opportunities for local residents;

• Impact on house prices;

• Impact on Open Space; and

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• Impact on Health.

Ecology

• Opportunity for public realm (and so potentially biodiversity) improvements.

Waste Management

• Operational waste generation, storage handling and disposal.

Summary of Environmental Considerations & Preliminary Assessment of Impacts

Noise and Vibration

6.4 Each of the route options/alignments will have potential to generate noise and vibration impacts; the most important of which are considered to be:

• Construction noise and vibration - potential noise and vibration from tunnel/shaft and station excavations

• Operational noise and vibration - vibration and reradiated noise from tube operations below ground, noise from ventilation shafts; and operational noise associated with use of the station

6.5 The purpose of this assessment is to ascertain any potential impacts on the noise and vibration sensitive receptors along the three proposed routes and to provide an indicative construction noise assessment based on preliminary information about the sites.

6.6 It has been assumed that excavation of the tunnels will commence at Battersea Power Station on completion of the station box and associated enabling works. A number of sites are currently being assessed for their suitability to act as temporary construction/shaft access locations as described in the Parsons Brinckerhoff Feasibility Report, December 2008 (PB Ref UMD90388A/0039/03).

6.7 Depending on the final route selection, there is the potential for above ground construction noise and vibration at construction sites. During construction, noise and vibration will be generated from construction equipment including tunnel borers and other excavation equipment and potentially heavy goods vehicle (HGV) movements. A full noise and vibration impact assessment will be undertaken as part of the EIA that supports the TWAO Application. The step-plate junctions at the Kennington Loop will be constructed through a combination of mechanised and hand-mining. Hand-mining will need to be closely monitored to ensure that operatives do not exceed maximum limits for exposure to vibration.

6.8 Noise and vibration mitigation will be required throughout the excavation and construction phase. Noise and vibration from excavation and construction activities will be controlled through the preparation, agreement [with the LBW and the LBL] and implementation of an Excavation and Construction Method Statement (ECMS).

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6.9 Operational noise is likely to consist of rail-induced vibration from the subsurface tube line and noise from passengers and service traffic at each of the associated stations. Operational noise is also expected from fan noise at ventilation shafts as they extract air from the tunnels below.

6.10 A full baseline noise assessment will be undertaken as part of the EIA that supports the TWAO Application.

6.11 Predicted noise levels exceed the criteria typically by around 1-5 dB(A) for all sections of line below sensitive receptors such as houses, offices, schools and churches. There is very little difference in effects for the different route options. Mitigating options for further consideration during the detailed engineering design include: Reduction in Unsprung Mass, Reduction in Primary Suspension Stiffness, Selection of appropriate Damper System, Resilient Wheels, Wheel Turning, Slip-Slide Control Systems, Continuous Welded Rail, Rail Straightness, Rail Grinding, Resilient Rail Fasteners, Booted Sleepers (or Sleeper Soffit Pads), Floating Slab Track, Slab Track and Continuous Rail Support and Sleeper Pitch. Further information on each of the above can be found in Section 5.3.1.6 of the URS Northern Line Extension Preliminary Environmental Assessment Report, Version 5, December 2008.

6.12 Based on the preliminary results from assessment of likely vibration impacts on the Oval Cricket Ground, it is unlikely that there will be significant affects from ground borne vibration in terms of building damage and human response.

Air Quality

6.13 The purpose of this assessment is to ascertain any potential impact to local air quality and the identification of any impacts associated with the three route options. Impacts on air quality could be as a result of emissions, including dust generation, during excavation/construction, as well as the operational emissions and indirect impacts associated with the completed extension.

6.14 In conclusion, a number of negligible and minor adverse impacts have been identified during the construction phase, during which construction dust is anticipated to have the greatest potential to cause nuisance to nearby receptors.

6.15 There are anticipated to be no moderate or major adverse residual impacts associated with the operational Northern Line Extension, except perhaps during emergency operational conditions such as tunnel fires. Indeed, a minor beneficial impact has been identified, associated with the anticipated reduction in road traffic movements in the area. With regards to the three route options, there are few identified advantages associated with any one route option over another, based on their potential to affect local air quality.

Ground Conditions & Water Resources

6.16 The purpose of this assessment is to evaluate the impact of the three route options on existing ground conditions and water resources within the study area, including a general geotechnical assessment of the potential for soil movements.

6.17 No significant impacts to the ground conditions are expected through the construction

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phase of any of the Route Options provided standard, good practice mitigation measures are applied.

6.18 Initial green field settlement assessments have been undertaken. These confirm the potential for ground movements, which should be evaluated in more detail when a full ground investigation has been undertaken. At the detailed design stage, much more work will be undertaken on the assessment of the risk of damage to the existing London Underground Limited (LUL) infrastructure, as well as to third party properties. Based on an assessment of the structures within a defined zone of influence, appropriate mitigation measures will be applied based on the assessed potential damage risk - this may include condition surveys and monitoring. A detailed register of structures within the zone of influence will be produced prior to any works commencing in order to determine the monitoring requirements.

6.19 Monitoring will be undertaken to demonstrate that settlement and other movement is taking place as predicted by the design, and to provide an advance warning where this is not the case. Monitoring may include electro level beams in tunnels and on structures, ‘tell tales’ or DEMEC gauges to monitor crack or joint movement in concrete or masonry; vibrating wire strain gauges to provide information on individual members; and extensometers to monitor changes in tunnel diameter. Both a combination of real time monitoring and point readings at agreed intervals will need to be used, according to the degree of risk assessed for each tunnel or structure. Monitoring will need to start in advance of the work to establish baseline readings. For lesser structures it maybe sufficient to undertake ’before and after’ condition surveys.

6.20 The majority of the potentially contaminated sites are situated along Route Option 3, providing the highest risk to creating preferential pathways to the underlying minor aquifer, highest risk to construction personnel and may generate a greater amount of potentially contaminated spoil. Route Option 3 further presents the highest risk of ground movements to sensitive overland structures.

6.21 The likely residual impact of any of the three Route Options on ground conditions following mitigation is considered to be negligible. Should remediation be required to clean up any contaminated soils associated with historic land uses, the remediation will result in a moderate permanent beneficial residual impact to the local environment.

6.22 A comprehensive ground investigation will be required for the preferred route to support the TWAO application. Following confirmation of the presence or absence of potential sources of contamination, a suitable remediation/mitigation strategy will be designed, if required.

Waste

6.23 An initial estimation of the amount of spoil to be excavated associated with each route option has been undertaken and a number of possible disposal locations have been identified.

6.24 Liaison continues with the Port of London Authority to develop an appropriate

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strategy for the handling and disposal of excavated material by barge on the River Thames, which is a policy they support. A Spoil Excavation and Management Plan will be developed between THL and PLA.

Ecology

6.25 A preliminary assessment of the three route options in relation to the ecological sensitivity of designated sites within the study area has been undertaken.

6.26 In summary, the estimated residual impact of each route option is considered to be negligible post mitigation. On completion of the underground tunnels and associated station(s), the potential for any adverse ecological impact diminishes. Operation of the completed tube line is considered to have no impact on the ecology of the Study Area.

Archaeology

6.27 Information on the known archaeological sensitivity of each of the three route options has been reviewed from a broad range of sources considered sufficient for identifying sensitive archaeological resources at the preliminary feasibility stage. A more detailed archaeological desk based assessment involving consultation of additional sources of information will need to be undertaken as part of the TWAO application and EIA.

6.28 Only ground disturbance at or close to current ground level would potentially have an archaeological impact with the bored tunnels being well below the level of anthropogenic strata and would not have an archaeological impact. Instead, all archaeological remains would be removed from the proposed ventilation shafts, and station box footprints. There would potentially be additional impacts within temporary construction compounds, for example, any crane bases, generators and compressors, ventilation plants, storage areas, offices, and car parking.

6.29 None of the three Route Options contain any Scheduled Monuments. All three cross Kennington Park, a Grade II Registered Park, and Archaeological Priority Areas (APAs) defined by London Borough of Wandsworth and the London Borough of Lambeth. All the Route Options have potential for previously unrecorded archaeological remains, particularly as they all cross Archaeological Priority Areas.

6.30 The least archaeologically sensitive route identified by this report is option 1 (direct from Kennington to Battersea Power Station). There are no known archaeological resources at the proposed locations of shafts and temporary works for this route option. The most archaeologically sensitive route is option 3. The route crosses Kennington Park (Grade II Registered Park) and 4 APAs, and contains the highest number of known archaeological receptors. In the 1970s, two large deposits of Delftware kiln waste material and significant stoneware vessels, considered of High Importance, were identified close to the route. In the case of option 2, two known resources of Low importance fall within the footprint of the proposed new station box; and in the case of route option 3, one known resource of Low importance falls within a proposed construction site.

6.31 Route option 2 is the only option to entail the construction of a new station, other than the BPS station, common to all options, and therefore, whilst not being the most

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archaeologically sensitive, represent potentially a greater impact on unknown archaeological resources than the other two options, as it would entail considerably more ground disturbance.

Socio Economics

6.32 A high level preliminary socioeconomic impact assessment of the three route options has been undertaken to consider the aspects listed below. A detailed investigation will be required to support the TWAO application.

6.33 Employment during the construction phase; Short term construction jobs and other direct and indirect employment generating a minor beneficial short-term impact on the Greater London economy.

6.34 Employment during the operational phase; A small number of new London Underground jobs generated by each of the route options.

6.35 Opportunities for local residents; All three Route Options will have a long-term major beneficial impact on opportunities for local residents by improving their access to work opportunities.

6.36 Impact on house prices; Preliminary results show that house prices in the area are likely to increase after completion of the three options.

6.37 Impact on Health; Although it is not possible to provide a detailed quantification at this stage, it is likely that the provision of an improved public transport service will reduce the number of trips made by car, with associated long-term moderate-major beneficial impact on congestion and traffic and thus on health and well-being for both local and London’s residents. It is not possible at this stage to precisely compare these Route Options, thus they are considered as equal for the purposes of this Preliminary Environmental Assessment.

Townscape and Visual

6.38 No detailed assessment has been undertaken of the likely visual impact of ventilation shafts and construction sites upon built heritage as part of the preliminary environmental assessment.

6.39 There are some shafts that are considered to be in particularly sensitive locations and will require very careful consideration at the detailed design stage. Route option 2 is potentially most sensitive in terms of townscape/visual/built heritage impacts as all of its potential shaft locations are in potentially sensitive areas. Route option 1 is perhaps the next-most sensitive, as it incorporates shafts on Kennington Green. Route Option 3 is considered potentially least sensitive.

Conclusions of Preliminary Environmental Assessment

6.40 The Preliminary Environmental Assessment has provided a high-level investigation into the likely environmental impacts of the three preferred options for an extension of the London Underground Northern Line from Kennington to North East Battersea/Battersea Power Station.

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6.41 The results of the preliminary environmental assessment as summarised in Table 38 indicate that, based on the currently available information regarding the three preferred options, any of the three preferred options under consideration for the proposed London Underground Northern Line Extension from Kennington to Battersea Power Station will provide significant socio-economic benefits such as employment generation and opportunities for local residents.

6.42 There is also expected to be a moderate beneficial impact from the removal of any contaminated spoil excavated during the construction of the extension (station boxes, running tunnels, step plate junctions and ventilation shafts).

6.43 Initial green field settlement assessments have been undertaken. These confirm the potential for ground movements, which should be evaluated in more detail when a full ground investigation has been undertaken. At the detailed design stage, much more work will be undertaken on the assessment of the risk of damage to the existing London Underground Limited (LUL) infrastructure, as well as to third party properties. Based on an assessment of the structures within a defined zone of influence, appropriate mitigation measures will be applied based on the assessed potential damage risk - this may include condition surveys and monitoring. A detailed register of structures within the zone of influence will be produced prior to any works commencing in order to determine the monitoring requirements.

6.44 Monitoring will be undertaken to demonstrate that settlement and other movement is taking place as predicted by the design, and to provide an advance warning where this is not the case. Monitoring may include electro level beams in tunnels and on structures, ‘tell tales’ or DEMEC gauges to monitor crack or joint movement in concrete or masonry; vibrating wire strain gauges to provide information on individual members; and extensometers to monitor changes in tunnel diameter. Both a combination of real time monitoring and point readings at agreed intervals will need to be used, according to the degree of risk assessed for each tunnel or structure. Monitoring will need to start in advance of the work to establish baseline readings. For lesser structures it maybe sufficient to undertake ’before and after’ condition surveys.

6.45 A minor beneficial impact to air quality due to the reduction in road traffic is anticipated, although this needs to be considered in more detail throughout preparation of the Transport and Works Act Order (TWAO) stage to account for the major redevelopment of the Vauxhall/Nine Elms/Battersea Opportunity Area.

6.46 Overall, there are anticipated to be a relatively small number of, localised, adverse residual impacts arising as a result of the excavation, construction and operation of the any of the three preferred route options in terms of air quality, noise and vibration, ground conditions/water resources and archaeology.

6.47 At this preliminary stage, Route Option 3 (via Vauxhall) was ranked as the most sensitive in terms of air quality, ground conditions and water resources, and archaeology, but least sensitive in terms of re-radiated noise from operation of the extension.

6.48 Route Options 1 and 2 were ranked as the joint least-sensitive routes in terms of air

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quality, ground conditions and water resources, but intermediately sensitive in terms of re-radiated noise from operation.

6.49 Route Option 1 was ranked as least sensitive in terms of archaeology, but least preferable in terms of beneficial socio-economic impacts.

6.50 Route Option 2 was ranked as moderately sensitive in terms of archaeology, but most preferable in terms of socio-economic benefits due to the proposed station in Nine Elms.

6.51 In terms of engineering feasibility, of the route options studied it is accepted within the wider design team, including LUL, that a new station at Vauxhall is the most challenging. LUL has raised concerns that the provision of an interchange at Vauxhall would not only adversely affect the existing station but would also likely affect stations along the Victoria Line, including Victoria Station.

6.52 Designs on Vauxhall are likely to be further frustrated by the recent announcement (October 2008) that the American Embassy plan to relocate from Grosvenor Square to a site in Nine Elms adjacent to the route of the proposed Vauxhall alignment.

6.53 A further, and more significant, complication at Vauxhall are the proposals currently being developed by LUL for the upgrade of Vauxhall Station. LUL has stated that the current options for a Northern Line interchange at Vauxhall are not coordinated with the step-free upgrade.

6.54 Further engineering/operational complexities associated with an interchange at Vauxhall include the vertical alignment of the tunnels in relation to the existing Victoria Line, connection to the Victoria Line platform, the ability of the existing ticket hall to accommodate additional loads posed by a Northern Line interchange, the potential for overcrowding; and the potential requirement for the closure of the bus station and surrounding roads to facilitate construction.

6.55 In summary, based on preliminary information available at the time of writing, it is considered that Option 2 (via a new station in Nine Elms) is the least environmentally sensitive option, and Option 3 (via Vauxhall) is the most environmentally sensitive option. Based on the engineering feasibility information available to the design team, it is assumed that the difficulties associated with the provision of an interchange at Vauxhall this site make it unviable.

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7. BUSINESS CASE METHODOLOGY

7.1 The extension of the Northern Line from Kennington to Battersea has been proposed as a public transport solution with sufficient capacity to support the proposed development at BPS and other development in the Nine Elms corridor, i.e. the whole of the OA. As such, the business case will be developed assuming the full development of the OA.

Scenarios to Be Tested

Demand Scenarios

7.2 The Nine Elms Opportunity Area Planning Framework is considering five development planning scenarios for the Nine Elms OA and each of these is to be modelled in Railplan by SKM. Scenario 5 includes the highest level of growth and is most consistent (in terms of order of magnitude) with the current development proposals at BPS.

Do-Minimum (without Tube extension)

7.3 The Tube extension has been proposed specifically because it is considered that only a rapid transit-based transport solution (plus additional bus services) could provide the capacity necessary to support the level of development growth in Scenario 5. Therefore the Business Case for the Tube extension will only be developed in relation to Scenario 5.

Do-Something (with Tube extension)

7.4 The same development assumptions will be used in the Do-Something and in the Do-minimum but distribution of the generated demand will take into account the presence of the Northern Line extension.

Fixed-Matrix Sensitivity Test

7.5 A fixed matrix modelling approach will be used, with the same public transport matrix assigned to the Do-Minimum and Do-Something scenarios. This would eliminate any uncertainty around forecasting of redistribution effects and mode-shift from car. Although this would effectively exclude public transport revenue impacts and journey time benefits to non-users, greater confidence could be had in the business case if it can be shown to be viable without these aspects. The detail of this modelling approach remains to be agreed with SKM.

Supply Scenarios

Do-Something (with Tube extension)

7.6 Modelling will be undertaken and a separate Business Case prepared for each route of the three options presented in the PB report.

7.7 In conjunction with each of these, reasonable assumptions of complementary adjustments to the bus network and frequencies will be modelled.

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Do-Minimum (without Tube extension)

7.8 Conventionally, a public transport business case would be prepared by reference to a Do-Minimum level of transport supply that reflects only the current level with the application of committed expenditure. This approach will be undertaken but, given the scale of development associated with Scenario 5, it is possible that this Do-minimum supply will be locally overwhelmed and lead to unhelpful modelling results. We will therefore also seek to investigate the business case by reference to an alternative “Do-Minimum Plus” or Reference Case, which assumes a realistic development of existing transport modes in response to very high demand growth in the corridor. This could be based on OAPF do-something transport assumptions for development growth Scenario 4 but this will be discussed with SKM. Thus we will seek to establish the following Do-Minimums

• Do-Minimum Supply –Based on committed expenditure only

• Reference Case Supply –Based on a ‘minimum’ capacity improvement to meet development demand, but within realistic constraints (possibly transport do-something for Scenario 4).

Summary of Scenarios for Testing

7.9 In summary, three business cases will be presented (one for each Tube extension option). If adequate modelling work can be obtained to support it, an alternative Business Case result will be presented for each of the three options appraised against both a conventional and a “Reference Case” Do-minimum.

Costs

Capital Costs

7.10 The technical feasibility study of the three Tube extension route options by PB has produced estimates of capital costs for each option. For the purposes of the Business Case appraisal, an allowance for Optimism Bias of 66% will be added, which DfT investment appraisal guidance suggests is appropriate to this stage of scheme development. The costs within the appraisal will be treated in accordance with the Business Case Development Manual.

7.11 The treatment of capital costs in the business case appraisal will be such as to reflect the full cost for the assessment of the economic Benefit to Cost Ratio (BCR).

Operating Costs

7.12 The forecasts of operating costs are set out in section.5.12.

Journey Time Benefits and Revenues

7.13 Model forecasts for 2026 will be used to assess journey time benefits and revenues. 2016 forecasts will also be incorporated if these are available from SKM. In that case a linear interpolation between the two years will be generated for the intervening period.

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Journey Time Benefits

7.14 Public transport journey time benefits for public transport users will be provided directly from the Railplan model.

7.15 A similar approach will be taken for the calculation of non-user (highway user) benefits, using the complementary Saturn model being developed by SKM.

Revenue

7.16 Revenue gains and losses will be considered for public transport as a whole. The Do-minimum and Do-something public transport matrices will be compared and appropriate yields will be applied to the matrix of patronage change. The derivation of these yields will be set out and discussed with TfL/LUL before the work is concluded.

Business Case Appraisal Framework

7.17 The overall approach to appraisal of the business case, in terms of appraisal period (60 years), discount rates, values of time and all other parameters for which guidance is available, will be as set out in the BCDM.

Consideration of Wider Economic Benefits

7.18 A qualitative review of likely wider economic benefits will be undertaken, leading to estimated additional impacts, benchmarked against other London transport schemes for which more detailed analysis has been undertaken at a later stage of development.

7.19 These will be used to identify a likely uplift factor which could be applied to the benefits estimated in the conventional business case.

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8. PROJECT RISKS

Process to Date

8.1 At the outset, work-stream leaders were asked to contribute their more prominent risks to form an initial risk register, which was coordinated by the programme management team.

8.2 A dedicated risk workshop was then held on Thursday 18th September 2008, which was attended by Treasury Holdings, representatives from the consulting team, including URS, Steer Davies Gleave, Parsons Brinckerhoff (and its subcontractors) and representatives of LUL.

8.3 The session attempted to identify project risks across a comprehensive range of impact areas. It also sought to assess the likelihood and impact severity of risks identified against high/medium/low scoring scales. The overall objectives of the workshop were to:

• Populate a risk register which can form the starting point for a risk management process throughout the project life cycle.

• Inform, at a high level, the estimation of capital and operating costs for the project.

• Enable differentiation of the three route options on grounds of cost, deliverability and safety risk.

8.4 The following scheme objectives were put forward as a basis for the workshop:

• To provide adequate public transport capacity and accessibility in support of London Plan objectives for the Vauxhall, Nine Elms and Battersea Opportunity Area.

• To complement the existing public transport network, particularly the tube, while avoiding unacceptable adverse impact on existing operations and transport planning.

• To promote sustainability, particularly by limiting growth in car use, and to have minimal environmental impact during construction and operation.

• To be realistically affordable through a private sector funding package.

8.5 A second risk workshop was then held on 10th October 2008, with the same group but a more extensive attendance from LUL. This workshop took account of the feasibility study’s initial conclusions, including preferred horizontal and vertical alignments and station arrangements. The risk register was further developed to incorporate the results of this workshop.

8.6 The top project risks for Route Option 1 (direct to Battersea with no intermediate station) are paraphrased below:

• Other funding partners slow to come forward or difficult to persuade into joining.

• Other developers object to the tariff under the OAPF or even to TWA by relationship.

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• Consultation on construction methodology results in conflicting requirements and scope creep.

• Noise and vibration impact on residents during construction of Step Plate Junctions, given relatively shallow depth.

• Lack of information leads to unidentified underground obstructions.

• OAPF recommends a planning scenario that does not justify the tube.

• Timing of project finance being confirmed prevents programming a small rolling-stock order to tag it onto an appropriate larger order

• LUL cannot be satisfied about proposed construction method at Kennington, particularly given recent changes to regulations.

• Operational risk of using a fleet that is potentially augmented with a few units of a slightly different type.

8.7 Building on the risks associated with the direct route, Route Option 2 (including a new Nine Elms station) has the following risks joining the top 10:

• Inability to reach an agreement with Sainsbury’s for station using part of their land

8.8 Route 3 (via a new interchange station at Vauxhall) has the following risks joining the top 10:

• Unable to satisfy Network Rail about proposed works in vicinity of their structures/land. Risk compounded by Network Rail process.

• Integration with existing systems not as expected (knowledge of historic or new systems, condition of old systems)

8.9 In summary, additional risk is incorporated in Route Option 2 (as compared to Route Option 1) by the introduction of an intermediate station. Route Option 3 incorporates a significant measure of further risk because of the nature of the proposed station and the alignment required to reach it.

8.10 A summary of the risk register for Route Options 1, 2 and 3 is included in the Parsons Brinckerhoff Feasibility Report, December 2008 (PB Ref UMD90388A/0039/03). It should be noted that not all risks have fully-developed mitigation measures identified yet.

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9. NEXT STEPS

Preliminary Feasibility Study and Business Case

9.1 The key dates for delivery of outputs from the Preliminary Feasibility Study and Business Case are summarised below:

• Final Engineers’ Preliminary Feasibility Report: 12th December 2008

• Final Preliminary Environmental Report: 12th December 2008

• Initial Business Case (initial forecasting results): *24th December 2008

• Final Business Case Report (final forecasting results): *Feb/March 2009.

*Note that these dates are estimated based on current expectations as to the availability of SKM modelling work.

Forward Programme of Scheme Development

9.2 An indicative TWAO programme is shown in Figure 9.1. In support of this, various important next steps need to be taken and further work commenced. The following summary sets out key requirements:

i. Formal approval of Preliminary Feasibility and Business Case by LUL/TfL;

ii. Initial formal consultation with key stakeholders in relation to routes considered and the outcome of the Preliminary Feasibility and Business Case studies;

iii. Possible further business case work to support decision-making following consultation;

iv. THL/LUL/TfL agreement of preferred Route Option;

v. Functional Specification drawn up and agreed between THL and LUL;

vi. Further development of joint promotion agreement between THL and LUL, building on existing heads of terms and formalising agreement of the Functional Specification;

vii. Establish project governance to allow sponsorship by both LUL and THL;

viii. Commission detailed feasibility study and engineering design;

ix. Commission detailed business case appraisal; and

x. Instigate process to make TWAO application:

o Definition of tactical approach.

o Coordination and preparation of application.

o Public consultation

o Proofs of evidence.

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FIGURE 9.1 PROVISIONAL TWAO PROGRAMME

Critical Issues for Ongoing Scheme Development

9.3 Various issues have been identified during this preliminary feasibility study and business case, which could not reasonably be resolved at this stage but which must be incorporated into the scope of ongoing scheme development. In most cases they should be given particular focus as early as possible. These are:

Construction access and permanent intervention shafts

• A full scoping study of possible locations for shafts on the preferred Route Option, with a view to selecting sites likely to be approvable under the TWA and possibly alternative sites. The alignment to be adjusted to accommodate these.

Alternatives for Kennington connections: Confirmation of optimal value/risk.

• Detailed investigation of the potential to implement a connection to the cross-tunnels between City and Charing Cross branches rather than to the turnaround loop at Kennington, potentially allowing the construction of step-plate junctions around these tunnels while they are not in operation and reducing construction costs.

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Stations and route

• Ongoing consideration of alternative sites for the Nine Elms station.

• Full development in parallel of alternative alignments not passing under the Oval cricket ground.

Operational assessment:

• Operational modelling to confirm performance and service robustness, with a view to confirming:

� The performance of Battersea station and cross-over and whether a lower cost design can be developed by use of a shorter length cross-over; and

� Whether or not a turn-back facility is necessary at Nine Elms.

Reradiated noise:

• Further consideration of reradiated noise during operation and the implications for scheme design.

Risks

• Further review of risks and other engineering issues in the issues register An Issues Register was also maintained alongside the risk management process during this Preliminary Feasibility Study and Business Case Assessment. Many of these have been acted upon during this phase of work. A list of residual issues has been included as Appendix A to this report, reframed as further actions to be taken up in the next stage of scheme development.

Conclusion

9.4 The preliminary feasibility study has shown that an extension of the Charing Cross branch of the Northern Line from Kennington to Battersea Power Station to support the development of the Battersea Power Station site and the Vauxhall / Nine Elms and North East Battersea Opportunity Area is feasible and could be taken forward to a more detailed study leading to a Transport & Works Act application.

Final Report

P:\Projects\7400s\7466\207466-H\Outputs\Final Report\Final version to Client\Northern Line Extension to Battersea & Nine Elms - Feasibility Study and Business

Case Methodology - Final Report.doc

Control Appendix

APPENDIX A

RESIDUAL ISSUES REGISTER

Final Report

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Business Case Methodology - Final Report.doc

Control Appendix

RESIDUAL ISSUES REGISTER

1 Spoil removal plan needs further development to confirm: Stock piling on site alongside other works, logistics and navigation for removal by river and final destination.

2 Interface between latest Battersea Power Station masterplan and latest station and cross-over design needs to remain coordinated.

3 Passenger congestion knock-on effects in other parts of the network need to be investigated and implications tackled.

4 Detailed work needed to understand necessary systems integration at Kennington

5 Further work needed to develop detailed integration with plans for other transport modes, including interchange.

6 Further work needed to demonstrate train capacity of the extension and likely level of service robustness.

7 More detailed work needed to tailor maintenance cost estimates for track and trains to specific features of this route (track curvature, S&C etc.)

8 A commercial strategy needs to be developed to manage the potential for a monopoly impact on cost of additional rolling stock (due to technical requirements)

9 Further work will be required to establish how additional Northern Line trains can be stabled and maintained within existing or new LUL Facilities.

10 Passenger demand for the Battersea extension from the Northern Line City branch needs to be investigated and understood and any necessary interchange improvements at Kennington then being addressed.

11 Coordination between ventilation strategies for Battersea Power Station masterplan (Eco-Dome) and tube station / tunnels (especially w.r.t. train movements) needs to be maintained to ensure effective separation.

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Appendix

12 Ground investigation will be required during further scheme development to reduce uncertainty about geology - in particular the levels of London Clay along the alignment – and confirm optimum tunnel levels.

13 The benefits of supporting large-scale development need to be emphasised in the way the business case appraisal is deployed and presented because these are not well demonstrated by the standard LUL Business Case Development Manual approach.

14 Investigation of the potential to implement a connection of the southbound line to the Kennington loop on a curved section under Kennington Park, with a view to reducing the cost of construction (and noting that this would require a derogation to LUL standards for track curvature;

15 Consultation and design required to establish what needs to be done in order to protect the EDF tunnel when tunnelling close to it?

16 Consultation and design required to establish what needs to be done in order to protect South West Storm tunnel when tunnelling close to it?

17 Consultation and design required to establish what needs to be done in order to protect Thames Water Ring Main when tunnelling above it.?

18 Coordination of the construction programme with that of the Battersea Power Station masterplan will be required to ensure space requirements for accommodating spoil and its removal at Battersea.

19 Finalised construction methods for Kennington Connections need to balance the avoidance of subsidence with construction impacts on residents.

20 There is a need to demonstrate to residents at Kennington that adequate mitigation is in place against construction impacts.

21 The programme and technical specification needs to be integrated with that for introduction of new signalling systems that are planned anyway.

22 There is a need to consult with emergency services (LFEPA) about location of intervention shafts.

23 Ongoing coordination with wider LUL network development plans is required to ensure that power supply proposals are adequate.

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Control Appendix

24 Further work needed to establish a detailed, publicly acceptable spoil removal plan for the Nine Elms station box.

25 A robust public consultation strategy needs to be developed.

Final Report


Appendix

Final Report



Control Appendix

APPENDIX B

BATTERSEA STATION AND CROSSOVER WORKING ASSUMPTION

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1282

8

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G M

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CAT

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XOB GNISSORC LENNUT DEROB AID 0094

59593 00793 50793

A

ANOITATS AESRETTAB

66753

5000

5000

50005000

LENNUT LCS

NO

PIL

ING

ZO

NE

NO

PIL

ING

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82000

LENNUT LCS

R=1288.800m

R=1288.800m

STRAIGHT

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m000.0051=R

m000.0051=R

3500

R=1288.800mSTRAIGHT

STRAIGHT R=1288.800m

STRAIGHT

STRAIGHT

4 No. EV15 TURNOUTS

Final Report



Control Appendix

CONTROL SHEET

Project/Proposal Name: NORTHERN LINE EXTENSION TO BATTERSEA AND NINE ELMS: FEASIBILITY STUDY AND BUSINESS CASE METHODOLOGY

Document Title: Final Report

Client Contract/Project Number:

SDG Project/Proposal Number: 207466-H

ISSUE HISTORY

REVIEW

Originator: Rupert Ingham

Other Contributors: Richard Randolph; Ian Sproul, text adapted from URS/PB reporting.

Review By: Print: Peter Twelftree

Sign:

DISTRIBUTION

Clients: THL – Tony Whitehead

LUL – Gordon Torp-Petersen, Phil McKenna, Alan Kerr

Consultant team – Rory McKimm (PB), Juliette Sedden (URS)

Steer Davies Gleave: PDT, RZR, RDI

Issue No. Date Details

V1

V2

V3

V4

Final

04/09/08

03/10/08

05/12/08

15/12/08

16/12/08

Draft for client / consultant team review.

Draft for client / consultant team and Gordon Torp-Petersen (LUL) for review Draft Final report for client / consultant and LUL review

Final draft issue to client / LUL Final issue to client / LUL

Final Report

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Appendix

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