DESIGN PRACTICE NOTE AXLE COUNTER RESET L1-CHE-INS-024 Version: 3 Effective from: 31 st August 2017 Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 1 of 16 Approval Amendment Record Approval Date Version Description 09/09/2015 1 Initial issue 01/02/2016 2 Updated with issue of Works Instruction & Signal Engineering comments 31/08/2017 3 Updates with Standard MTM axle counter reset, use of supervisor reset, capture of Human Factors elements with the DPN.
Transcript
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 1 of 16
Approval
Amendment Record
Approval Date Version Description
09/09/2015 1 Initial issue
01/02/2016 2 Updated with issue of Works Instruction & Signal Engineering comments
31/08/2017 3 Updates with Standard MTM axle counter reset, use of supervisor reset, capture of Human Factors elements with the DPN.
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 2 of 16
17 References and Legislation ............................................................................................. 16
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 3 of 16
1 Purpose The purpose of this DPN is to provide the axle counter reset requirements and the requirements for the associated reset panels located within the equipment housings.
This Design Practice Note supersedes all previous axle counter reset Requirements, Design Practice Notes, and Standards.
2 Scope This document is to clearly define MTM’s requirements in relation to VRIOGS 12.0.3 Revision A, Section 5 – Application Principles for Axle Counters.
This Design Practice Note shall apply to all existing Axle Counter Systems that are to be changed due to new or upgraded works, or Projects utilising Axle Counter Systems in a Siding, Main line or Overlay environment, unless approved by the Head of Engineering, Signals.
It shall be used in accordance with MTM Type Approval conditions for use and Manufacturer’s specifications for the Product.
This document contains information affecting Axle Counter Operating Procedures and Maintenance Work Instructions.
3 Abbreviations and Acronyms AXC Axle Counter DC Direct Current DPN Design Practice Notice I/O Input and Output IP Ingress Protection LED Light Emitting Diode MTM Metro Trains Melbourne OIC Officer In Charge RA Reset Acknowledgment REB Relocatable Equipment Building SER Signal Equipment Room SMT Signal Maintenance Technician T Track Circuit VRIOGS Victorian Rail Industry Operators Group Standard WS Point Supervisor Section WSR Point Supervisor Section Relay
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 4 of 16
4 Definitions For the purpose of this DPN the following terms are defined as follows:
Authorised Person Is an SMT, OIC, or Signal Supervisor who is authorised as being competent to reset Axle Counter Track Section(s) by the Head of Engineering, Signals as described within L1-CHE-WOI-002.
Automatic Reset The ability of the Axle Counter System to automatically reset Axle Counter Track Sections when specific conditions are met within the product’s manufactured design.
Axle Counter Head(s) The trackside interfaces of the Axle Counter System; mounted on the rail. The location(s) of the counter heads define the physical extent of the relevant Axle Counter Track Section(s).
Axle Counter System(s) A SIL4 system, which detects the presence or absence of rail traffic within given Axle Counter Track Section(s).
Axle Counter Track Section
Individual track section that uses Axle Counter Heads to define entry (exit) limits.
Axle Counter Track Section Reset
A reset function of an Axle Counter Track Section to restore an axle count to zero, stating that the Axle Counter Track Section is clear.
Axle Counter Evaluator The Axle Counter Evaluator is located within the indoor housing, consisting of a configured backplane, communication card(s), and power supply card and connects via cable to the trackside located Axle Counter Heads. It also connects the single Axle Counter Evaluator into the Axle Counter Track Configuration Network.
Axle Counter Track Configuration Network
The network architecture that connects the Axle Counter Evaluators into a designed configuration.
Clearance Point The boundary location on the Axle Counter Track Section where an axle/wheel may be positioned such that rail vehicles or trains, inclusive of overhang, are deemed to be clear at converging points or other locations.
Co-operative Reset Co-operative Reset is where a secondary independent check is utilised in addition to the controlling Signaller to confirm the Axle Counter Track Section is clear and the correct Axle Counter Track Section is being reset.
Disturbed Axle Counter An Axle Counter Track Section which indicates ‘occupied’ due to a miscount, communication issue or equipment fault.
Immediate Reset Resets executed as soon as the request is received by the Axle Counter System independent of the last wheel count in or count out.
Overlay Axle Counter System
Axle Counter Track Section(s) that are overlaid over existing track circuits.
Main Line(s) A track (other than a Siding), which is used for through rail traffic movements; inclusive of terminal platforms.
Next Train Reset A reset independent of last wheel count in/out that allows the Axle Counter Track Section to clear after a successful completed train passage through the Axle Counter Track Section.
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 5 of 16
Non-Technical Axle Counter Reset
A reset associated with a miscount of axles not related to an equipment failure.
Occupation Reset This is used for occupation type activities and works, such as powering up the Axle Counter System, after or during occupation works. (e.g. maintenance track works).
Parallel Inputs Individual inputs into an interlocking from an Axle Counter Track Section output relay for the Axle Counter Track Section.
Point Supervisor Section The Point Supervisor Section comprises of four or more Axle Counter Track Sections, whereby the first (entry) Axle Counter Head is compared to the last (exit) Axle Counter Head for Point Supervisor Axle Counter Section occupancy status.
The Point Supervisor Axle Counter Section can cover more than one track and comprises the outer Axle Counter Heads, but not the ones within the Point Supervisor Axle Counter Section (see Figures 2 and 3).
Point Supervisor Section Reset
When either of the first (entry) or last (exit) Axle Counter Head(s) fails, the Supervisor Axle Counter Track Section shall be reset through the appropriate keyswitch and pushbutton when the axle Counter equipment is healthy.
Point Track Locking Track Sections
Is the Axle Counter Track Section that dead locks the points that the Axle Counter Track Section covers.
Primary Configuration A configuration where the Axle Counter System is the only form of train detection.
Product The approved Axle Counter System supplied for use by the manufacturer or supplier.
Road Rail Vehicle A works vehicle that can be placed on track mid-section of an Axle Counter Track Section.
Reset Configurations The types of permissible Axle Counter System reset types within MTM areas.
Serial Inputs Axle Counter Track Section output(s) from an Axle Counter Evaluator communication card(s) to a serial connection to the interlocking.
Siding(s) A track where rail vehicles can be placed clear of a Main Line.
Signaller The person in charge of the working of points and signals from an interlocking apparatus or signal control panel.
Supervisor Configuration A configuration whereby two Axle Counter Track Sections are configured and contained into a larger Axle Counter Track Section.
Supervisor Reset When the Supervisor Axle Counter Section as part of a Supervisor Configuration is clear following a train movement, then each of the individual Axle Counter Track Sections contained within the supervised section will be reset automatically when the axle Counter equipment is healthy.
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 6 of 16
Supervisor Axle Counter Section
The Supervisor Axle Counter Section is comprised of two Axle Counter Track Sections, whereby the first (entry) Axle Counter Head is compared to the last (exit) Axle Counter Head for Supervisor Axle Counter Section occupancy status.
Technical Axle Counter Reset
A reset associated with a technical failure of the axle Counter equipment and not related to a miscount of axles. This will require an Authorised Person to operate the reset panel in the field.
Train Controller The person directing rail traffic movements under the ‘Train Control System’.
Symbol Symbol for an Axle Counter Head. The filled in square defines to which rail the Axle Counter Head is attached. This symbol shall be used on Signalling Arrangement and Bonding Plans.
5 Background MTM Network Safety Axle Counter Reset Requirements within L1-OPS-PRO-025 General Operating Procedures for axle counter applications on the MTM Network.
This document provides the requirements for resetting Axle Counter Track Sections after a fault event or following completion of Infrastructure Maintenance activities which have disturbed the Axle Counter Track Section(s).
6 The Issue This DPN clarifies the Technical Axle Counter Reset arrangements for all Products and is an update to VRIOGS 012.0.3 Signalling Principles - Axle Counter Application, Revision A, Section 5.
7 Axle Counter Reset Overview When an Axle Counter Track Section is indicated as occupied due to an Axle Counter System failure, the system shall be able to automatically reset the Axle Counter Track Section through the Supervisor Reset function.
1) Should this form of reset fail, due to a technical restriction or failed supervisor section or the supervisor count for the affected section being reached, then an Authorised Person will need to perform an Technical Axle Counter Reset (Next Train or Occupation Reset) as described in Section 10. The reset will be operated at the trackside equipment housing for the Axle Counter Evaluator through the reset panel for the given Axle Counter Track Sections.
2) The reset panel is the interface between the Authorised Person and the Axle Counter System. The panel has a track plan overview for all the Axle Counter Track Sections for which the Axle Counter Evaluators are housed at the specific location (see Figure 6). The panel has a keyswitch for each type of Technical Axle Counter Reset and a pushbutton for each Axle Counter Track Section, that when operated together will initiate a reset request to the Axle Counter Evaluator, which will then execute the reset request.
3) Subject to which keyswitch is operated, the Axle Counter Evaluator will reset the Axle Counter Track Section immediately or after the next train has traversed the section. The pushbutton has a red LED to provide an indication of the track occupancy or reset status for each Axle Counter Track Section.
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 7 of 16
4) Additional to the technical resets, the Operations Procedure of the Railway Operator shall be obeyed at all times.
8 Operational Procedures 1) Prior to Axle Counter Track Sections being reset, the Authorised Person shall
communicate with the Signaller. The Signaller is to advise the Authorised Person where the train(s) is in relation to the Axle Counter Track Section(s) that have failed and are required to be reset.
2) The Signaller and Authorised Person are to be in communication in accordance with MTM General Operating Procedures L1-OPS-PRO-025.
9 Axle Counter System Requirements The below system user requirements apply to Axle Counter Systems.
1) The Axle Counter Track Section reset shall be used for clearing track occupancy of a Disturbed Axle Counter in the event of an in-field attendance to repair a fault, or activities conducted within the confines of an Absolute Occupation, Booked Out Track or Track Force Protection.
2) Axle Counter Systems shall be interlocked with the signalling system for the Axle Counter Track Section occupancy detection. The Axle Counter Track Section occupancy interface between the signalling interlocking and the Axle Counter System can be either a parallel or serial input for Axle Counter Track Section occupancy purposes.
3) The interlocking system shall not be used for the purpose of resetting an Axle Counter Track Section without approval from the Office of the Chief Engineer. This allows for a less complicated and simplistic design.
4) There is no requirement for Technical Axle Counter Resets from Train Control for Main Line and Siding train detection Axle Counter Systems (except for the Frankston to Stony Point line signalling).
5) All Axle Counter Track Sections shall be indicated in the same manner as traditional track circuits in relation to Train Control panels, maintenance and diagnostic systems.
6) There is no requirement to indicate the Axle Counter Track Section reset status to the diagnostic systems.
7) The automatic reset ability of the Product shall be used within the axle counter design in accordance with this DPN.
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 8 of 16
10 Axle Counter Reset The following reset configurations shall apply.
10.1 Supervisor Reset If a Supervisor Reset is provided by an Axle Counter System, this shall be used as the primary form of resetting an Axle Counter Track Section.
1) If the Supervisor Axle Counter Section is clear, then each of the individual Axle Counter Track Sections (contained within the supervised section) shall also be clear. This enables the Disturbed Axle Counter (and any other Disturbed Axle Counter) sections within the Supervisor Axle Counter Section to be automatically reset when the Axle Counter Track Sections are healthy.
2) The designer of the Axle Counter configuration is responsible to ensure the application of the Supervisor Reset could not lead to a track section being reset with a train still in section. Road Rail Vehicles that enter and exit the rail between Axle Counter Sections shall be considered when using this form of reset configuration.
3) For resets over points refer to Section 10.4.
10.2 Next Train Reset A Next Train Reset is used when the Supervisor Reset is unavailable and a Technical Axle Counter Reset is required or when resetting over points as explained in Section 10.4.
1) The Next Train Reset is provided by the Authorised Person operating the reset keyswitch and then the pushbutton on the reset panel (see Section 11 for details on the reset panel).
2) The operation of the reset keyswitch and pushbutton provides a command to the Axle Counter System to reset the Axle Counter Track Section count to zero and primes the system for the next train to traverse the section to complete the reset. The track section shall remain occupied until a successful count in and count out of the track section (refer to Figure 1).
3) The Next Train Reset key shall be retained within the keyswitch. Refer to Section 13.
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 9 of 16
10.3 Occupation Reset This is used for occupation works, such as powering up the Axle Counter System, after or during a commissioning.
1) The Authorised Person shall operate the occupation keyswitch and then the pushbutton for the Axle Counter Track Sections to be reset on the reset panel (see Section 11 for details on the reset panel).
2) The operation of the keyswitch and the pushbutton shall provide a command to the Axle Counter System to immediately reset the Axle Counter Track Section (refer to Figure 1).
3) The Occupation Reset can also be used for resetting point locking Axle Counter Track Sections under occupation works and is explained in Section 10.4.
10.4 Axle Counter Resets Over Points The Axle Counter System shall allow for resetting of Axle Counter Point Track Locking Track Sections over points (refer to Figure 4 for point locking external relay reset circuit).
1) To facilitate this, the Axle Counter Heads shall be positioned at least at the track section clearance point(s).
2) The reset shall only be applicable to the lay of the points at the time the Axle Counter Track Section failed; based on the points being locked in that position. The designer of the Axle Counter System shall ensure this is safe for each application.
3) Supervisor Sections over points may be provided to allow Technical and Non-technical Axle Counter Resets of the Axle Counter Point Track Locking Track Section(s) (see Figures 2 and 3).
4) The Axle Counter System shall provide a vital point supervisor section output to drive a vital relay (WSR) that is energised when the point supervisor section is clear (the point supervisor section is all the Axle Counter Track Sections over the points, which is within the green lines shown in the examples (see Figures 2 and Figure 3)).
5) The Authorised Person shall select the appropriate keyswitch and pushbutton on the reset panel for the failed Point Track Locking Track Section.
I/O Card
Immediate Reset
Next Train Rest R
Axle Counter Track Section Reset Pushbutton
Reset Keyswitch
Figure 1. Non-Point Fouling Track Sections
R
Occupation Keyswitch
LED
LED Green LED for Occupation Keyswitch
Green LED for Reset Keyswitch
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 10 of 16
6) Using an external relay circuit (WSR), subject to the keyswitch and pushbutton(s) selected and the status of the WSR relay, the design configuration shall automatically select either an Immediate or Next Train Reset (see Figure 4). For example, referring to Figure 2, should the Axle Counter Head at the centre of the crossover fail, 650T and 651T will require to be reset. Assuming the reset keyswitch is operated (i.e. not within an occupation) with the WSR relay energised with 650 and 651 pushbuttons operated, then both Point Track Locking Track Sections shall be immediately reset. If the WSR was de-energised, then both Point Track Locking Track Sections shall require a Next Train Reset.
7) Should the Supervisor Reset not be available, then the Authorised Person shall select either the Immediate or Next Train Reset using the appropriate keyswitch and pushbutton on the reset panel.
8) The use of either the Immediate or Next Train Reset without the Point Supervisor Section Proving shall ensure that the Axle Counter Track Section to be reset is clear of any obstruction and the Railway Operational Rules shall be followed before initialising the reset.
9) In the event of a technical failure on either of the point supervisor Axle Counter Heads (e.g. the Axle Counter Heads positioned at the extremities), a reset shall be performed through the reset keyswitch and pushbutton for the Point Supervisor Section (see Figure 4).
622T (AXC)
721T (AXC)
620T (AXC)
720T (AXC)
622T/X1043T 620T/622T
721T/X1048T 620T/721T 720T/620T D621T/720T
Figure 3. Point Supervisor Sections
WS 620
700T (AXC) 650T (AXC) 652T (AXC)
701T (AXC)
651T (AXC)
653T (AXC)
Figure 2. Point Supervisor Sections
WS 650/651
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 11 of 16
10.5 Road Rail Vehicles
The Axle Counter System shall not require any Axle Counter Track Section to be reset when road rail vehicles entering and exiting the rail corridor from either road rail vehicle pads or level crossings. The Axle Counter System shall provide configuration to prevent Axle Counter Track Sections becoming occupied.
The use of track circuits for this purpose is not permitted.
11 Axle Counter Reset Panel 1) The Next Train and Occupation Resets shall be initiated by an Authorised Person on the
reset panel provided in the equipment housing.
2) The reset panel shall have the track plan showing all the Axle Counter Track Sections, reset keyswitches and pushbuttons for the location (refer to Figure 5).
3) The area of control for the track plan shall be associated with the corresponding Axle Counter Evaluator(s) located within the equipment housing.
4) To reduce the risk of human error, the reset pushbuttons shall be located on a geographical layout as per the example in Figure 5.
5) Where the Axle Counter Track Section has its Axle Counter Evaluator in two or more locations, there shall be a reset pushbutton provided on the reset panel in each location.
6) Engraved labels shall be provided to clearly identify the functionality of each keyswitch and pushbutton.
I/O Card
Next Train Reset
Immediate Reset
R
Point Supervisor Axle Counter Section
Axle Counter Track Section
Reset Pushbutton
Reset Keyswitch
Figure 4. Point Fouling Track Sections
R
Occupation Keyswitch
I/O Card
Point Supervisory
Section
650/651WSR
650/651WSR
650/651WSR
LED
LED Green LED for Occupation Keyswitch
Green LED for Reset Keyswitch
Immediate Reset
Next Train Rest
R
Point Supervisor Section Reset Pushbutton
Reset Keyswitch
R
Occupation Keyswitch
LED
LED Green LED for Occupation Keyswitch
Green LED for Reset Keyswitch
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 12 of 16
7) The reset panel shall be at an approved location taking into consideration infrastructure maintenance and human factors requirements including with respect to accessibility.
8) The reset panel shall be enclosed within a secure housing to prevent tampering of the reset key switches or inputs.
Figure 5. Reset Panel Layout
Figure 6. Typical Reset Panel for Primary Detection Layouts
Reset Keyswitch
Occupation Keyswitch
700T
602T
704TT
703T
603T
701T
No Indication in Pushbutton – AXC Track Section Not Occupied Red Indication in Pushbutton – AXC Track Section Occupied
702T
705T
Flashing Red Indication in Pushbutton – Acknowledgement from Evaluator for Next Train Reset
602/603WST
Evaluator No 1
Evaluator No 2
Pushbutton with Track Section occupancy indication
Key Switch
Geographical Reset Panel for the location
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 13 of 16
12 Equipment Housing 1) Depending on the Axle Counter System architecture, the Axle Counter Evaluator and
reset panel may be placed in SERs, REBs or lineside equipment locations.
2) In all situations, the reset facilities shall be securely housed, with adequate space and accessible only by Authorised Person(s).
13 Keyswitch A keyswitch shall be provided for a Next Train Reset and another provided for the Occupation Reset. Each keyswitch shall have a green LED indication when the key is turned fully to the Reverse position.
Only one keyswitch shall be operated at any one time along with the Axle Counter Track Section Reset pushbutton. The keyswitch provides protection against accidental or unauthorised axle counter reset(s), as well as selecting the type of reset to be performed.
The keyswitches shall:
1) Only be activated via an approved issue signalling key (Protec 7P).
2) Have a minimum IP rating of IP53 and suitable for outdoor locations.
3) Be operable only to the left (RESET ENABLED) or reverse position.
4) Hold the signalling key captive when not in the centre position.
5) Only release the inserted signalling key when the keyswitch is in the centre position.
6) Be spring returned to the centre position.
7) Be positioned to allow ease of accessibility and operation.
8) Provide normally open contacts in the centre position which become closed in the left or reverse position.
9) Be manually held in the left or reverse position whilst the pushbuttons are operated.
14 Pushbutton A reset pushbutton shall be provided for each Axle Counter Track Section where the associated Axle Counter Evaluator is in the housing.
The pushbutton and the keyswitch held reverse shall provide an input to the Axle Counter Evaluator to execute the applicable reset for each Axle Counter Track Section.
The pushbutton shall: -
1) Have a bezel or similar surround device to protect against accidental operation of the pushbutton.
2) Be able to display a red LED indication within the centre of the pushbutton.
3) Have a minimum IP rating of IP53 and suitable for outdoor locations.
4) Be positioned to allow ease of accessibility and operation.
5) Not be able to be latched in the pressed (in) position.
6) Be spring return to the un-pressed (out) position.
7) Provide normally open contacts in the un-pressed (out) position, which become closed in the pressed (in) position.
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 14 of 16
8) Be located on a panel showing the track layout. Refer to Figure 5.
9) Have an Axle Counter Track Section occupied indication (red colored indication) within the pushbutton. Refer to Figure 5.
10) Have an Axle Counter Track Section Reset acknowledgement (flashing red indication) within the pushbutton, Refer to Figure 5.
Table 1 - Pushbutton Indications
PUSHBUTTON INDICATION
MEANING
No light (LED extinguished)
Axle Counter Track Section is clear or potentially a failed LED.
Steady red light Axle Counter Track Section is occupied or an Axle Counter Track vacancy detection failure.
Flashing red light Next Train Reset command received and accepted (reset acknowledgment set) by Axle Counter System (waiting for the next train to traverse section).
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 15 of 16
15 Relays, Indications and Power Supplies 1) The pushbutton LED indications shall be supplied by type approved power supplies to
allow for a steady indication and a separate power supply for the flashing bus for a flashing indication.
2) The Next Train Reset acknowledgment indication is provided by either a vital or non-vital output from the Axle Counter Evaluator.
3) The Axle Counter Track Section clear and reset acknowledgment outputs for each track section shall drive a vital DC biased miniature relay type 2MBA4-4 (The Axle Counter Track Section on one side of the relay and the reset availability on the other side). These will be used for vital track vacancy detection for the signalling interlocking and for the pushbutton indications (refer Figure 7). This is also for Point Supervisor Sections.
4) The Points Supervisor Reset relay shall be via an approved vital DC biased miniature relay.
16 Responsibilities A full safety risk assessment (Including safety in design and operational safety) shall be produced by the Design Authority for all scenarios that may arise during the resetting of axle counter track sections.
Next Train Reset Availability xxx RA
xxx T
I/O Card
Track Section Output
Figure 7. Outputs and Indications
xxx RA xxx T
xxx RA xxx T LED B
FB
N
N
N
B
B
Red LED within Reset Pushbutton
DESIGN PRACTICE NOTE AXLE COUNTER RESET
L1-CHE-INS-024 Version: 3 Effective from: 31st August 2017
Approving Manager: Chief Engineer Approval Date: 31/08/2017 Next Review Date: 31/08/2020 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION Page 16 of 16
