Introduction
Following Amey’s completion of the GRIP 4 single option selection phase of the scheme they were awarded a GRIP 5-8 design and build contract to implement the new signalling. The project consisted of; provision of additional signal sections on both up and down lines between Lostwithiel and Largin at Bodmin Parkway, and on both up and down lines between Liskeard and St Germans east of Menheniot.
Amey were contracted to deliver the design for signalling, Civils, E&P and Telecomms. All designs were subject to a rigourous IDC process to ensure they were fully integrated.
The work included provision of new axle counter train detection sections along with their related reset facilities. Alterations were required at Plymouth, Lostwithiel and Liskeard Signal Boxes.
Geographically, the East Cornwall line is double track from Par to Saltash with a single line section over the East Largin viaduct between Bodmin Parkway and Liskeard.
Challenges
The main challenge of the scheme centred around the amount of different technologies within the project area; signalling between Lostwithiel and Liskeard is SSI controlled by an Entrance-Exit (N-X) Panel at Lostwithiel SB, the signalling at Liskeard is Electro Mechanical Controlled by lever frame & block shelf at Liskeard SB, the signalling from Liskeard to St Germans is route relay (E10K) controlled by N-X Panel at Plymouth PSB. Existing signals are a mixture of colour light, motorised semaphores and mechanical semaphores.
To overcome the challenge of the many different technology types Amey assembled a specialist signalling design delivery team where each design package was led by an experienced designer with specific knowledge of the existing equipment type. This approach required careful programming given the amount of parallel design activities required to achieve the commissioning date.
Throughout the design Amey engineers closely collaborated with Network Rail engineers and operations staff to ensure a solution that was agreeable to everyone was produced.
Innovation
The operational axle counter reset requirements were for both conditional and unconditional facilities. Traditionally, all axle counter reset facilities were conditional which caused significant operational delays following engineering work which is why unconditional reset using an Engineers Possession Reminder were introduced. Such controls are fairly common in SSI hence the controls could be provided for the new sections at Bodmin Parkway in the Liskeard SSI interlocking using already available templated design, however, at Menheniot bespoke controls were required within the existing E10K Route Relay Interlocking at St Germans since unconditional axle counter reset facilities had never previously been provided at that particular type of Route Relay Interlocking.
The alterations to facilitate the axle counter reset circuitry at St Germans was developed from first principles. Due to the complex and bespoke nature of the circuits Amey designed a single template example that was issued for internal comment by installation and testing teams prior to submission to NR for review and scrutiny. The approach of producing template designs allowed a robust template to be developed and agreed prior to completion of all the control circuits reducing the amount of rework required.
Success
The core design works were delivered over a challenging 12 month design programme which culminated in a successful commissioning in April 2018 (in readiness for the introduction of a new timetable in December 2018).
Amey’s design team worked in close collaboration with both the Amey installation & testing teams and the NR Project Engineers to ensure the design requirements were fully understood and to minimise comments during the NR acceptance period.
Commissioning of the new signalling was successfully completed inline with the original programme enabling the train operator, GWR, to realise the benefits by operating additional trains in the 2018 timetable.
Testimonials
For further reading see Rail Engineer article “Cornwall's Capacity Triumph”, which was written with contributions from Paul Mundy, the Network Rail Designated Project Engineer for the scheme.
Here is the author’s concluding statement:
“The project has cost around £30 million. Cornwall Council has contributed £15.1 million (of which £11.9 million was from the European Regional Development Fund) with the remainder funded by the Department for Transport. In monetary terms, this is moderate expenditure and represents good value. The extreme rationalisation of BR days has been reversed by a pragmatic approach. Perhaps more importantly, the impact of almost making this a local scheme, where changes to requirements can be discussed and agreed between the Network Rail project engineering staff and the contractor, has yielded considerable benefits to both time and cost.”