T697 Trials Final

8/2/2019 T697 Trials Final

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Research Programme

EngineeringInvestigation into the use of bio-diesel fuel

on Britain's railways: Service trials on

South West Trains and First Great Western


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Copyright

RAIL SAFETY AND STANDARDS BOARD LTD. 2009 ALL RIGHTS RESERVED

This publication may be reproduced free of charge for research, private study or for internal

circulation within an organisation. This is subject to it being reproduced and referenced

accurately and not being used in a misleading context. The material must be acknowledged asthe copyright of Rail Safety and Standards Board and the title of the publication specified

accordingly. For any other use of the material please apply to RSSB's Head of Research and

Development for permission. Any additional queries can be directed to [email protected].

This publication can be accessed via the RSSB website: www.rssb.co.uk.

Published March 2010
mailto:[email protected]://www.rssb.co.uk/http://www.rssb.co.uk/mailto:[email protected]


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Executive Summary .................................................................................................1

Introduction ..............................................................................................................2

Methodology.............................................................................................................2

Summary of service trial experience ........................................................................3

Conclusions..............................................................................................................5Recommendations ..................................................................................................5

Service Trial 1 - SWT ...............................................................................................6

Vehicle details ..................................................................................................................6

Trial details .......................................................................................................................6

Fuel consumption monitoring ...........................................................................................7

Oil analysis .......................................................................................................................8

Reported problems...........................................................................................................8

Post-trial actions...............................................................................................................8

Service trial 2 - FGW..............................................................................................13Vehicle details ................................................................................................................13

Trial details .....................................................................................................................13

Fuel consumption monitoring .........................................................................................17

Oil analysis .....................................................................................................................18

Reported problems.........................................................................................................19

Post-trial actions.............................................................................................................19

Summary of service trial experience ......................................................................24

Appendix 1 - ULSD fuel analysis (South West Trains)...........................................27

Appendix 2 - B20 fuel analysis (South West Trains)..............................................29

Appendix 3 - Cylinder inspection of NTA855-R3 engines in 159007,Cummins report CUK090204-01, 3 February 2009 ...............................................31

Appendix 4 -'SWT NT 855 Rail bio trial fuel pump & injector report,Cummins report CUK090526-SR, 20 May 2009 ....................................................33

Appendix 5 - B20 fuel analysis (First Great Western) ............................................38

References.............................................................................................................40


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RSSB 1

Bio-diesel service trials onSouth West Trains and First Great Western

1 Executive Summary Earlier work by RSSB and ATOC had investigated the effect ofbio-diesel use on UK rail traction diesel engines by conducting a

desk-top study followed by test bed evaluation on selected engine

types. The third and final part of this project comprised service

trials, undertaken by South West Trains (SWT) and First Great

Western (FGW) on their Class 159 (one three-car unit) and 165/

166 (centre vehicle of four units) vehicles respectively, detailed

within this report. A 20% bio-diesel blend with ultra-low sulphur

diesel (ULSD) was selected for both trials, representing the

maximum that could reasonably be sustained without significant

performance or reliability effects on the vehicles, based upon the

preceding test work.

Comprehensive monitoring arrangements were instigated for

both trials, with particular reference to the monitoring of fuel

consumption. For SWT, the trial unit was monitored on gas oil

prior to biodiesel operation, whereas for FGW the consumption of

the centre vehicles was compared directly with that of the end

vehicles. This latter approach provided more robust andconsistent data.

Both trials completed successfully, with a maximum period on

B20 operation of 11 and 9 months for SWT and FGW

respectively. No problems attributable to B20 operation were

experienced during the trials.

The measured fuel consumption increase exceeded that

expected based on stable full load test bed data by a factor of 2.4

and 2.8 for SWT and FGW respectively, resulting in deteriorations

of 6.9% for the Cummins (SWT) and 16.8% for the Perkins (FGW)

engine types used. One FGW set was the exception, with a fuel

consumption improvement recorded of some 9%. The reasons for

these discrepancies could not be investigated further within the

confines of this project, but is assumed to be primarily due to

differences in engine power settings or operating condition.

There were no problems identified from the oil analysis results

that were attributable to B20 operation.

If further biodiesel operation was to be considered, either as a trial

or a more general introduction, it is recommended that a

maximum 20% blend ratio is used, based upon the satisfactory

results from these service trials. The impact on the engine fuel

consumption should also be investigated in detail at an early


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2 RSSB

stage in order to quantify the increase and establish as far as is

practicable the reasons for it.

2 Introduction In 2006, an investigation into the use of biodiesel on UK railwayswas commenced by RSSB/ATOC. This comprised an initial

desktop study (reference 1), followed by test bed evaluations on

dedicated engines (reference 2) and in-service trials. This

process followed that developed for the earlier trials of sulphurfree diesel (SFD) fuels.

Two of the three train operators who had previously undertaken

the SFD trials were willing to participate in the service evaluation,

these being South West Trains and First Great Western. This

would enable the existing infrastructure procured for the SFD

project and installed at Salisbury and Reading depots to be

reused for this trial. For details of this equipment see reference 3.

The structure of, and results from, these trials are detailed in this

report.

3 Methodology The principles of the service trial were similar to those previouslyadopted for the SFD trial, where specific vehicles would be

selected for fuelling with biodiesel over a proposed 6-month trial

duration. Fuel consumption would be monitored throughout the

trial and any relevant problem areas recorded. Oil analysis details

would also be maintained.

Monitoring guidelines were produced for both trials, again based

on the successful operation of the previous SFD trials (references

4 and 5).

Comparative fuel consumption data would be provided by either

a baseline period of monitoring with the trial vehicles in standard

condition or by separate standard vehicles during the trial.

Agreement from both the vehicle owner and engine overhauler

was obtained before proceeding with each trial. The agreement of

the latter was sought partly to ensure continuity of warranty cover,

considered to be best practice and useful for future reference.

Based upon the test bed performance results and the views of the

engine manufacturer/overhauler, a 20% (B20) biodiesel ratio was

selected as being the highest blend to trial before issues ofperformance or reliability may have become more significant.


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RSSB 3

4 Summary of service

trial experience

It is clear that neither trial produced any particular problems in

service, providing confidence that a 20% concentration of biofuel

can be tolerated in existing service engines. However, there are

two corollaries to this:

1 For the Cummins engines, rubber and copper components

were renewed prior to the start of the trial (see section 7).

2 The long-term effects on the engine are unknown and canonly be quantified at engine overhaul.

The boroscope inspection of the SWT engines has assisted in

quantifying item 2, with no adverse indications identified

attributable to biofuel operation. The early submission of one of

the FGW engines for overhaul as noted in section 8.6, will further

assist the interpretation of engine condition. Overall, the evidence

to date indicates that operation on a B20 blend will not have a

significant impact on engine reliability or durability.

In terms of engine performance, generally the fuel monitoring

arrangements worked well with regular and reliable data receivedfrom Salisbury and Reading depots. However, the SWT

monitoring would have benefited from more consistent and

sustained monitoring of a comparison vehicle or set.

Where this was achieved with the FGW trial, it provided an

effective ongoing comparison between gas oil and ULSD/B20

operation, particularly with the standard vehicles being part of the

same set. Thus, variations in operating diagrams and engine

running time were immediately eliminated. This would seem to be

the preferred approach for future trials of this nature.

Analysis of the data over successive four-week periods also

smooths the data effectively, minimising the effect of week-by-

week variations where a day's missing fuel data (inevitable on an

occasional basis) would have a more significant effect on a

weekly comparison.

Continuation of monitoring for a nominal period after the

completion of B20 operation has also clearly demonstrated how

the fuel consumption of the trial vehicles reduced back to the level

of the comparison vehicles.

Of more concern was the level of fuel consumption increase

observed with three of the FGW vehicles, with an average

increase of some 16.8%. This compares with an increase of


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4 RSSB

nominally 6% from the combined change from gas oil to ULSD to

B20 from test bed results at full load with this engine type (lower

loads were of a similar magnitude or less). Although this increase

was significantly greater than expected, the data is consistent for

three sets, particularly given the return to previous gas oil

consumption levels referenced above.

The reason for this discrepancy between test bed and service

conditions is not clear. It cannot be accounted for by densityvariations between gas oil and B20 alone.

Further measurements of additional parameters on all three

engines of the set would be required to clarify the situation further,

for example boost pressure readings to establish whether all

three engines were operating at the same power level.

Differential power settings are considered to be the most likely

explanation and any wider introduction of biodiesel fuel will need

to investigate this factor further at an early stage. In principle, this

may also apply to the inevitable transition from gas oil to sulphur-

free fuel expected within the next two years.

Similarly, the situation with the fourth vehicle whereby improved

fuel consumption was obtained cannot be explained further within

the parameters of this project. However, at least part of this

apparent increase may be due to poorer performance of one end

vehicle (58120) where the consumption regularly reduces below

1.4 miles per litre, reducing the apparent 'saving' on 58620

slightly.


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RSSB 5

5 Conclusions 1 Two service trials with a 20% biodiesel fuel blend (B20) withULSD have been successfully completed on South West

Trains and First Great Western. No problems attributable to

operation on biodiesel were reported during the trials.

2 Monitoring of fuel consumption has been maintained

throughout both trials, resulting in a mean consumption on

B20/ULSD of 1.48 miles per litre for SWT and 1.1 to 1.4

miles per litre for FGW.

3 For both trials, the increase in fuel consumption on most

sets was greater than expected compared with preceding

test bed assessments, resulting in a 6.9% increase for SWT

and 16.8% increase for FGW (on three sets). For the

respective engine types, the test bed increases were 2.9%

and 6% respectively based on stable full load data. One

FGW vehicle produced an improved fuel consumption of up

to 9%.

4 The reasons for these discrepancies could not be

determined without further measurement and investigation,outside the scope of this project.

5 Although comments could be made on certain oil analysis

results, there were no adverse indications considered to be

directly attributable to operation on B20 fuel.

6 Boroscope and fuel injection inspections carried out on the

SWT trial engines showed no adverse characteristics from

B20 operation.

6 Recommendations 1 If further biodiesel trials or operation were considered, theseshould be limited to a maximum B20 blend unless therewere satisfactory technical and/or commercial reasons for

increasing the blend ratio.

2 If further biodiesel trials or operation were considered, the

impact on the engine fuel consumption should be

investigated in detail at an early stage and as a matter of

some urgency in order to quantify the increase and

establish as far as is practicable the reasons for it. In

particular, this should examine and quantify any relevant

differences between the test bed fuel consumption results

and methodology and the service trial monitoring.


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7 Service Trial 1 - SWT7.1 Vehicle details A 3-car Class 159 unit was selected for the trial (159007), fitted

with 2005-build Cummins NTA855R3 engines, rated at 300kW.

All three vehicles of the set were to be fuelled on B20 during the

trial. The centre vehicle of the set (58724) was fuelled from the

official start of the trial to gain experience, followed by the other

two vehicles (52879 and 57879) some seven weeks later.

Table 1 summarises the engine details. All engines were fitted

following a normal overhaul.

7.2 Trial details All inspection requirements identified in the monitoring document

(reference 4) were advised to have been carried out prior to trial

implementation. Prior to the start of the trial, Cummins had

advised the following necessary actions in order to protect the

engine warranty:

Replacement of copper piping in contact with the fuel.

Replacement of nitrile rubber components in contact with

fuel with Viton components.

Engine overhaul after the tests.

Oil sampling.

The bio-diesel element of the fuel was sourced from a UK supplier

(Greenergy) and was understood to be a mix of European-

sourced rape seed oil and US-sourced soya oil. This would be

mixed with ultra-low sulphur diesel (ULSD).

Fuel samples of both ULSD and the B20 blend were submitted for

analysis prior to the start of the trial (appendices 1 and 2).

The first biodiesel delivery was supplied to Salisbury depot on 25

February 2008, with 58724 fuelled on B20 from 29 February and

the other two vehicles fuelled on ULSD from that date. Fuel

Table 1 - SWT engine details

Vehicle Engine serial no. Date fitted

52879 29118760 18/07/07

58734 29119177 12/10/07

57879 29118762 26/09/07


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RSSB 7

monitoring was initiated on all three vehicles from the same date.

The remaining two vehicles of the set started operation on bio-

diesel from 19 April 2008.

The biodiesel supply was being funded by RSSB as part of the

overall project budget. A lower than expected fuel spend enabled

the trial to be considerably extended, finally terminating on 1

February 2009, representing a total operating period of 11 months

on the longest running vehicle, and just over 9 months on theremaining vehicles.

7.3 Fuel consumption

monitoring

Fuel consumption data was supplied on a weekly basis

throughout the trial. Figure 1 shows the fuel consumption in miles

per litre for successive weeks of the trial. Although miles per litre

is a mix of imperial and metric units, mileage and fuel

consumption data was received in these units and this arguably

provided a more readily understood figure.

Interpretation is difficult due to the variability of the data, but there

is an indication that 58724 and 57879 were experiencing an

inferior consumption towards the end of the trial period.

It had originally been intended (reference 4) that the remainder of

the Class 159/0 fleet would be used for a comparative

assessment of fuel consumption; however data for the rest of the

fleet was not received. Some data was available from a single

standard unit (159014) over a six-week period in the middle of the

trial and this has also been added to figure 1. This also suggests

a worse consumption on the ULSD/B20 mix compared with the

standard fuel, although again the trends are variable.

An overall mean from all three vehicles over the complete trial

duration gives a figure of 1.484 miles per litre. This is some 5.1%

better than the average from the two end vehicles on ULSD during

the first seven weeks and 6.9% worse than gas oil based on the

159014 data. This compares with a nominal 2.9% deterioration in

specific fuel consumption identified from the test bed results for

this engine type for the change from gas oil to ULSD/B20 (coupled

to a similar percentage power decrease).

Thus it is difficult to be precise concerning an accurate effect on

fuel consumption. Monitoring would have benefited from a more

consistent assessment of a comparison vehicle or vehicles.

However, it would seem reasonable to suggest that the overall


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8 RSSB

variations experienced are within the normal operating duty cycle

data from the SWT fleet.

7.4 Oil analysis Oil sampling is scheduled for every BX exam, or every 14,500

miles. Oil analysis data (carried out for SWT by Qinetiq) was

received for approximate 3-4 week intervals up to Dec 08/Jan 09,

with the exception of 58724 for which no sample data was

received after 26 August 2008.

In general, there were no major issues with the oil analysis, with

any observed trends representing the expected wear

characteristics of this engine type.

The most notable events are shown in figures 2 and 3. Figure 2

displays an increase in fuel dilution (reduction in viscosity) on

52879. This is characteristic of rail traction applications with their

inherent engine idling and resultant unburnt fuel passing the

piston rings into the crankcase. This could be exacerbated by use

of biofuel, but the rate of dilution is not considered excessive and

remained within acceptable overall limits.

Figure 3 shows the variation in iron, copper and lead levels in

57879. The NTA855R3 engine type does demonstrate increases

in these elements up to a certain level, but the copper/lead

bearing materials here are particularly high.

Qinetiq's recommendation at that time was to change the oil,

which was clearly done, but the trends can be seen to be re-

establishing themselves following the oil change. A crankcase

blow-by test was carried out by Cummins to check cylinder

integrity, and the results were within specification. No further oil

sample results were received by Interfleet.

7.5 Reported problems For efficiency, assessment of the relevance of any problems

experienced in service was carried out at Salisbury depot. No

problems relating to the use of biodiesel were reported to

Interfleet during the trial.

7.6 Post-trial actions Prior to the start of the trial, it had been provisioned for the trial

engines to be stripped down by Cummins at the end of the trial

when the set went for C4 overhaul. It was latterly agreed that

since the engines had not operated on B20 for a full overhaul

period, a specific engine strip would not be carried out. Instead,

an endoscope inspection would be conducted, and an injector/fuel pump change carried out, with the latter components being

sent away for separate inspection.


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RSSB 9

This activity was carried out following trial completion. Cummins

advised on 16 March 2009 that the inspections had been

completed, and that a meeting was to be arranged with SWT to

discuss the oil analysis results, following which a report would be

produced.

Two reports have since been received from Cummins, included

as appendix 3 and appendix 4 covering the endoscope and fuel

injection equipment inspections respectively. For the engine, theconclusion was that operation on B20 fuel had had no detrimental

effect on the cylinders. A similar conclusion was reached for the

fuel injection equipment, with the comment made that its condition

was within the specified Cummins guidelines and could have

been reused.

As at the date of this report, none of the engines used in the trial

have yet been renewed.


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RSSB 13

8 Service trial 2 - FGW8.1 Vehicle details For the FGW trial based at Reading depot, it was decided to use

two 3-car Class 165 and two 3-car Class 166 units, with the centre

car of each set being fuelled with biodiesel. Due to delays in

commencing biodiesel operation, several months monitoring on

gas oil was achieved initially. Subsequently, the start dates on

B20 for the centre cars were staggered by several weeks.

Table 2 summarises the vehicle and engine details. The intention

was to select one early life, two mid-life and one later life engines.

Note that unit 165103 operated on gas oil only from the start of

the monitoring period until March 2009, when an FGW

operational decision replaced this unit with 165102. Details of the

individual engines in set 165103 have therefore not been included

in the table.

8.2 Trial details All preliminary requirements identified in the monitoring document

(reference 5) were understood to have been carried out prior to

trial implementation. This included a health inspection by DiPerk,

the Caterpillar agents, in line with appendix E of the monitoringdocument.

The biodiesel element of the fuel was sourced from a UK supplier

(Greenergy). It had been the intention to use a different supplier

for the purposes of diversity, but this would have taken longer to

achieve. The biodiesel was mixed with ultra-low sulphur diesel

(ULSD).

Fuel monitoring was commenced on 8th September 2008 on all

vehicles of the four original sets. ULSD/Biodiesel operation on the

centre vehicle started on the following dates (in sequential order):

58607 - 14 December 2008

55428 - 4 January 2009

58620 - 9 March 2009

55416 - 23 March 2009

With six-month trial duration for each vehicle, this would have

resulted in completion dates between 14 June and 23 September

2009. In reality, it was decided to extend the trial duration on the

first vehicles such that all four vehicles ceased B20 operation at a

similar time upon exhaustion of the final biodiesel delivery. This

meant that the fourth vehicle concluded its trial prior to six

months, but any further running would have required a freshblending by the supplier with an expected higher price as a result

of general increased fuel costs.


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14 RSSB

The actual trial termination dates for each vehicle were as follows

(approximate trial duration in brackets):

55416 - 1 August 2009 (5.5 months)

55428 - 1 October 2009 (9 months)

58607 - 25 August 2009 (8 months)

58620 - 27 August 2009 (5.5 months)

The fuel system incorporates fuel heaters, for which agreement

would be required from the manufacturers for operation on B20

fuel. The Eberspacher Hydronic 30 fuel heaters were only

approved for biodiesel operation up to a maximum of B10 blend.

However, following discussions between FGW and Eberspacher,

it was agreed that FGW would order two new Hydronic 30 heaters

to go with two units already on trial, and that these four would be

fitted to the four biodiesel trial vehicles. On this basis,

Eberspacher agreed to support the warranty.

It was intended to submit a sample of both the ULSD and B20 fuel

as carried out for the SWT trial. However, Greenergy advised that

as they do not blend all the fuel on site, they could not guaranteethat the ULSD sample would be from the batch of fuel to be used

for the trial. It was therefore agreed to submit only a single B20

sample for analysis (appendix 5).

From the Qinetiq analysis, the only result worthy of comment was

the percentage FAME content of only 15%. This was contrary to

the expectation of 20% 2%, i.e. a minimum FAME content of

18%. This was raised with Greenergy, who supplied further data

from their own analysis, identifying a FAME content of 19.1% and

19.3% from two recent sets of tests.

Further clarification established that the Qinetiq test was carriedout using FLM 190, whereas the Greenergy analysis was

according to BS EN 14078. These tests are similar, but FLM 190

measures FAME content by weight-to-volume (w/v), whereas the

BS EN test measures volume-by-volume (v/v). If the 15% FLM

190 w/v test result is divided by the measured density of 0.844 kg/

m3, then this gives 17.8% v/v, still low, but closer to the minimum

18% level. Qinetiq further advised that in their experience the

repeatability of FAME content processes is typically 1%,

thereby potentially bringing this result above the minimum

expected level.

With this closer comparability, it was decided that no furtheraction was required.


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Table 2 - Summary of vehicle and engine details for the FGW trial

Unit No. Vehicle No. Engine No. Date of last

overhaul

(m/y)

Date of

next

overhaul

(m/y)

Last exam

type and date

Mileage a

start of tr

Biodiesel trial

vehicle

Vehicle 1 165102 55416 077957P 18/04/07 07/10 B2, 03/03/09 214,591

Vehicle 2 165114 55428 067933N 07/12/06 07/10 B5, 23/12/08 198,249

Vehicle 3 166207 58607 047616N 27/04/07 02/10 B5, 06/11/08 251,118

Vehicle 4 166220 58620 088049R 30/01/08 06/11 B7, 02/03/09 100,570

Comparison

vehicle

Vehicle 1 165102 58917 088067R 18/06/08 01/12 B2, 03/03/09 10,188

Vehicle 2 - 58954 067867N 28/06/08 07/09 B2, 03/03/09 342,749

Vehicle 3 165103 58918 - - - - -

Vehicle 4 - 55417 067935N - - - -

Vehicle 5 - 58955 - - - - -

Vehicle 6 165114 58929 077993P 08/10/07 01/11 B5, 23/12/08 127,611

Vehicle 7 - 58966 088078R 01/08/08 09/11 B5, 23/12/08 35,208

Vehicle 8 166207 58120 057763M 12/04/05 03/09 B5, 06/11/08 365,446


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Vehicle 9 - 58128 077981P 23/08/07 07/11 B5, 06/11/08 67,880

Vehicle 10 166220 58120 057781M 20/07/05 03/11 B7, 02/03/09 137,679

Vehicle 11 - 58141 067883N 08/08/06 12/09 B7, 02/03/09 291,927

Table 2 - Summary of vehicle and engine details for the FGW trial

Unit No. Vehicle No. Engine No. Date of last

overhaul(m/y)

Date of

nextoverhaul

(m/y)

Last exam

type and date

Mileage a

start of tr


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RSSB 17

8.3 Fuel consumption

monitoring

Fuel consumption data was supplied on a weekly basis

throughout the trial. Figures 4 to 7 show the consumption in miles

per litre (these units retained for the same reasons as for the SWT

trial) for each set, divided into four-weekly periods. Analysis of the

data showed that this provided a more consistent result than a

weekly assessment. The effect on each set is discussed below. In

each graph, the period on B20 is shown by a dotted line.

Set 165102 (figure 4) operated on ULSD/B20 from the start of fuelmonitoring, reverting back to gas oil on 1st August 2009. Over the

first two four-week periods, an improved consumption was

recorded. The subsequent three periods showed a change to a

consistently reduced consumption, with a mean deterioration of

some 15.7% compared with the two end vehicles. The reason for

an earlier improvement is unknown. Restoration to gas oil

operation for a further three periods showed the centre vehicle

consumption readily matching that of the end vehicles.

For set 165114 (figure 5), the first four periods (solely on gas oil)

show a deteriorating fuel consumption for all three vehicles. Giventhe time of year (September to December), at least part of this

effect was considered to be due to climatic variations. Once

55428 was operating on ULSD/B20, a consistent reduction in

consumption was evident, averaging some 11.2% over periods 7

to 14. The consumption for period 14 did match that of the end

vehicles, suggesting that the transition back to gas oil had

occurred before the advised date of 1st October (there was a

small degree of uncertainty). A subsequent four week period on

gas oil again readily matched that of the end vehicles.

The shortened operating time on gas oil for set 166207 (figure 6)

showed reasonably consistent consumption. With 58607

operating on ULSD/B20, a consistent reduction in fuel

consumption was evident, averaging some 23.5% over periods 5

to 13.

Resumption of gas oil operation for a single five week period

readily matched the centre vehicle consumption with that of the

end vehicles.

Over at least the first four-week period for each of the sets

commented on above, the fuel consumption of the centre vehicle

remained broadly comparable to the end vehicles, indicating adelayed effect of the B20 fuel in significantly affecting the engine's

fuel consumption.


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18 RSSB

Set 166220 (figure 7) showed a gradually deteriorating fuel

consumption during the initial monitored periods on gas oil, albeit

to a lesser degree than set 165114. With 58620 on ULSD/B20, a

consistent improvement in consumption (although not on a

consistent week-by-week basis) was noted, averaging some 9%

over periods 8 to 13. Restoration to gas oil over two periods

retained the improved consumption of the centre vehicle.

Overall, the fuel consumption of the set end vehicles was typicallyin the region 1.4 to 1.7 miles per litre, with the centre vehicle being

within the range 1.1 to 1.4 miles per litre. Set 166220 was the

exception, with inferior consumption on the end vehicles (1.3 to

1.5 miles per litre) and improved consumption on the centre

vehicle (around 1.6 miles per litre). The reason for this

discrepancy has not been investigated further, but may be due to

relative power settings of the engines and/or general engine

condition.

For the three sets showing inferior consumption, the average

increase was 16.8%.

8.4 Oil analysis The following oil analysis data was available from the centre cars:

55416 - 4 samples between 22/3/09 and 29/07/09




No oil analysis data was available from the end vehicles.

The number of samples supplied is limited, particularly given the

oil additions between samples affecting any underlying trends.

However, the following comments can be made.

55416 - A gradual build-up of insoluble matter, but not to

extreme levels.

55428- High lead level on penultimate sample.

58607 - Internal coolant leak on final sample.

58620 - High levels of copper initially, subsequently

reducing (but affected by oil additions).

None of these results can sensibly be attributed to the use of the

B20 fuel.


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RSSB 19

8.5 Reported problems Shortly after the start of B20 operation on the first vehicle (58607),

it was identified that the engine fuel pump had been renewed on

22 October 2007 due to low power and the engine not reaching

maximum speed. It is understood that the pump change resolved

these problems.

Vehicle 55416 was identified as being low on power before it

started operation on biodiesel. Consequently, a fuel injection

pump change was carried out on 17 May 2009, with no further lowpower reports.

No other engine or fuel system-related problems were reported

during the trial.

8.6 Post-trial actions It was agreed that all four engines would be subject to inspection

when overhauled at the conclusion of their scheduled operating

period, with the intention of identifying any feature or

characteristic that may have been affected by the use of

biodiesel. The expected removal dates were as follows:

047616N (58607) 23-01-2010 067933N (55428) 23-07-2010

077957P (55416) 07-09-2010

088049R (58620) 04-04-2011

Engine 047616N was actually removed early, being received at

Caterpillar in late-October 2009 having accumulated 361,498

miles. Although unexpected, this has had the advantage of

minimising the period of operation on gas oil following trial

completion and hence reducing the potential effect of sustained

subsequent running on that fuel. The precise reason for changing

the engine is not recorded, but is assumed to be due to loss of

engine oil as a result of a failed compressor delivery pipe two

days previously (the second experienced on this engine). There

was nothing specific on RAVERS to identify whether the engine

change was due to these previous faults. There had been no call-

outs to DiPerk for attention to this engine.


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9 Summary of service

trial experience

It is clear that neither trial produced any particular problems in

service, providing confidence that a 20% concentration of biofuel

can be tolerated in existing service engines. However, there are

two corollaries to this:

1 For the Cummins engines, rubber and copper components

were renewed prior to the start of the trial (see section 7).

2 The long-term effects on the engine are unknown and canonly be quantified at engine overhaul.

The boroscope inspection of the SWT engines has assisted in

quantifying item 2, with no adverse indications identified

attributable to biofuel operation. The early submission of one of

the FGW engines for overhaul as noted in section 8.6, will further

assist the interpretation of engine condition. Overall, the evidence

to date indicates that operation on a B20 blend will not have a

significant impact on engine reliability or durability.

In terms of engine performance, generally the fuel monitoring

arrangements worked well with regular and reliable data receivedfrom Salisbury and Reading depots. However, the SWT

monitoring would have benefited from more consistent and

sustained monitoring of a comparison vehicle or set.

Where this was achieved with the FGW trial, it provided an

effective ongoing comparison between gas oil and ULSD/B20

operation, particularly with the standard vehicles being part of the

same set. Thus, variations in operating diagrams and engine

running time were immediately eliminated. This would seem to be

the preferred approach for future trials of this nature.

Analysis of the data over successive four-week periods also

smooths the data effectively, minimising the effect of week-by-

week variations where a day's missing fuel data ( inevitable on an

occasional basis) would have a more significant effect on a

weekly comparison.

Continuation of monitoring for a nominal period after the

completion of B20 operation has also clearly demonstrated how

the fuel consumption of the trial vehicles reduced back to the level

of the comparison vehicles.

Of more concern was the level of fuel consumption increase

observed with three of the FGW vehicles, with an average

increase of some 16.8%. This compares with an increase of


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nominally 6% from the combined change from gas oil to ULSD to

B20 from test bed results at full load with this engine type (lower

loads were of a similar magnitude or less). Although this increase

was significantly greater than expected, the data is consistent for

three sets, particularly given the return to previous gas oil

consumption levels referenced above.

The reason for this discrepancy between test bed and service

conditions is not clear. It cannot be accounted for by densityvariations between gas oil and B20 alone.

Further measurements of additional parameters on all three

engines of the set would be required to clarify the situation further,

for example boost pressure readings to establish whether all

three engines were operating at the same power level.

Differential power settings are considered to be the most likely

explanation and any wider introduction of biodiesel fuel will need

to investigate this factor further at an early stage. In principle, this

may also apply to the inevitable transition from gas oil to sulphur-

free fuel expected within the next two years.

Similarly, the situation with the fourth vehicle whereby improved

fuel consumption was obtained cannot be explained further within

the parameters of this project. However, at least part of this

apparent increase may be due to poorer performance of one end

vehicle (58120) where the consumption regularly reduces below

1.4 miles per litre, reducing the apparent 'saving' on 58620

slightly.


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Appendix 1 - ULSD fuel analysis (South West Trains)


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Appendix 2 - B20 fuel analysis (South West Trains)


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Appendix 3 - Cylinder inspection of NTA855-R3 engines in159007, Cummins report CUK090204-01, 3 February 2009


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Appendix 4 -'SWT NT 855 Rail bio trial fuel pump &injector report, Cummins report CUK090526-SR,20 May 2009


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Appendix 5 - B20 fuel analysis (First Great Western)


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References1 'Investigation into the use of bio-diesel fuels on Britains railways', RSSB, March 2007.

2 'Evaluation of Engine Operation on Biodiesel Fuel', Interfleet Technology report ITLR-T19495-

001, 30 May 2008.

3 'Investigation into the use of sulphur-free diesel fuel on UK railways, RSSB, June 2007.

4 'Biodiesel Service Trials: Monitoring Guidelines for South West Trains', Interfleet Technology

report ITLR-T19495-002, 11 January 2008.

5 'Biodiesel Service Trials: Monitoring Guidelines for First Great Western', Interfleet Technology

report ITLR-T19495-003, 29 July 2008.


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