ETCS and Axle Counter Introduction

The Great Western Mainline ETCS Project introduces European Train Control System (ETCS) Level 2 overlay from Paddington Station at 0m to 12m along the Great Western Mainline, including the Heathrow Branch. This programme of works is the first ETCS deployment across a mainline railway and at a terminus station. 

Scope

HSRS have lead and supported the System Safety Assurance activities for Great Western Mainline ETCS Project stages T1 (replacement of track circuits with Frauscher Axle Counters between Paddington and Reading) and TB2 (ETCS overlay between Heathrow Airport Junction and Acton). These activities were used to demonstrate compliance with CENELEC standards EN50126 & EN50129, which in turn, were also used to support Network Rail's CSM-RA deliverables.


Stage T1 was commissioned in December 2021 whilst Stage TB2 was commissioned in November 2023.

 

Scope deliverables included authorship and delivery of, for both stages:


  • Hazard Identification Workshops, as well as associated briefing notes and reports.


  • Balise Installation Safety Reports.


  • Application Conditions Compliance Reports (for Smartlock 400 and Frauscher FAdC R2 Application Conditions).


  • Specific Application Safety Reports for both the Interlocking and Axle Counter Sub-Systems, as well as for the ETCS Project Solution.


  • Risk assessments against specific ETCS system architecture decisions (e.g., balises utilised at points and protective balises for trains in Level 2 SR mode).


  • Safety Reviews in support of Project Readiness Gate Reviews.


  • Safety analysis and verification of change requests.


Delivery Challenges

  • Working with the ETCS subsystem, which is both complex and less established in the UK.


  • Working with international teams on technical problems.


  • Widening of HSRS scope as the project continued.

Benefits


As part of our activities we have brought a number of benefits to the project:


  • Identification, management, and subsequent closure/transfer of project hazards, safety requirements, and product application conditions. These have required multiple HazID workshops as well as structured meetings with project engineering staff in order to identify appropriate requirements and closure evidence.


  • Explicit risk estimation process utilised to assess specific risks arising from ETCS architecture decisions and to justify appropriate solutions. These have been used to close hazards and have been directly referenced in safety reports for the ETCS solution.


  • Support of each balise installation, required prior to stage commissioning, through the delivery of balise installation safety reports. These have been used to justify that there are no un-accounted for safety requirements necessary for closure prior to each balise installation.


  • Gathering of evidence required to support the readiness reviews of the project for each stage gate. This has allowed the project to pass to the next gate (GO) in a timely fashion without issuing a NO-GO prior.


  • SRP and External ISA approval of the Interlocking & Train Detection Specific Application Safety Report in support of Stage T1 commissioning.


  • SRP approval of the ETCS Solution Specific Application Safety Report in support of Stage TB2.
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