Great Western Mainline Electrification

End Client

Infrastructure Manager


Engineering Safety Case Management


United Kingdom


2018 - 2019

Key Stakeholders

  • Network Rail Route System Review Panel (NR SRP)
  • Network Rail Operations
  • Assessment Body (CSM-RA AsBo)
  • Train Operating Companies

Lifecycle Involvement

Detailed Design to Site Operation


The Great Western Electrification Program was part of the biggest investment in the Great Western mainline since Brunel built it more than 150 years ago. Electrifying Britain’s oldest and busiest railway has helped make it greener, quieter and more reliable for people, as well as increasing capacity with five new fleets of trains.


HSRS provided Engineering Safety Case Management for this multi-billion pound scheme, gaining the required endorsements for the energisation of multiple route sections and the subsequent running of electric trains.


We also helped generate the Technical File that supported the Declaration of Verification (ECDV-TF) from Maidenhead to Didcot which was Authorised for Placing into Service by the ORR in Dec-17.

Benefits Delivered

There were a number of challenges surrounding the project:

  • Route section system safety documentation did not align with the energisation events, potentially leading to gaps in the safety justification submissions. 
  • The project Hazard Record contained ~900 entries with safety requirements not adequately developed, therefore the Hazard Record was not compliant to the CSM RA Regulations and difficult to focus on key hazardous events.
  • Unclear submissions timescales to achieve authorisation; potentially leading to rushed and uncontrolled submissions to the CSM RA ASBO and the SRP. 
  • Unclear understanding from project teams across the line of route of the endorsements required from internal and external assessment bodies and review panels to achieve successful Entry into Service and Authorisation for Placing into Service.
  • Hazard Transfer process not sufficiently implemented with TOCs, potentially leading to residual risks not being accepted and potential commissioning delays.

Our Solution

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

  • Consolidation of the Hazard Record, greatly reducing the number of entries to a focused and manageable level.
  • Regular engagement with the ASBO of project status and timely response to Assessment Records that were produced for each key deliverable, helping to bring the ASBO on the CSM RA journey that helped lead to supportive Safety Assessment Reports.
  • We developed a submissions strategy that allowed suitable review periods for the ASBO and System Review Panel and presented this to individual route section delivery teams and the route SRP, helping get internal and external stakeholders aligned with the requirements to achieve Entry into Service events. 
  • Our Safety Justification Reports clearly articulated the outstanding compliance evidence at the point of submissions with each being tracked through to the point of commissioning and communicated to SRP, the ASBO and the route Head of Engineering, demonstrating a controlled approach to closing items within the Hazard Record.
  • Status presentations to Senior Sponsor, Programme Managers and Engineering Delivery Director that gave confidence to allow for signing of Declarations of Control of Risk (DOCOR), and then ultimately SRP. 
  • Regular Hazard Transfer sessions were held with Great Western Railway to ensure that they were provided with all appropriate evidence and transfer forms in a timely manner given they had not previously operated in a 25kV electrified railway.

Related Services

System Safety Engineering (CSM-RA Compliance)

National Technical Specification Notices (NTSN) Conformance

Reliability, Availability, and Maintainability (RAM)

Training and Webinars

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