Network Rail Crossrail ARS signalling power renewal

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Amey electrical expertise was at the heart of a signalling power upgrade that has helped to eliminate costly delays on Network Rail’s western route

The renewal of the signalling power at five Crossrail sites in west London was a vast undertaking that hinged on Amey’s long-standing expertise with earthing and bonding. Following Amey’s successful introduction of ARS (auto-reconfigurable system) technology on an earlier project, Network Rail tasked the team with renewing the power distribution system along the whole stretch of line between Paddington and Hayes to make it ARS compliant.

The story began at Acton in 2014, when Amey began work on a project to prepare for the construction of a 730 metre long dive-under that would allow London-bound Elizabeth Line trains to pass underneath freight trains. Amey’s role was to explore ways to safely relocate location cases containing signalling, telecoms and other electrical equipment for the duration of the works, moving them back when construction was complete.

With the exception of a few brief shutdowns at weekends, the operation had to be carried out while trains continued to run. An auto-reconfigurable system allows sections of cable to be temporarily isolated, with power rerouted automatically to ensure no loss of supply. Amey’s ARS design allowed the electrical equipment to be moved with no interruption of power to the signalling.

Network Rail recognised the wider benefits of ARS on the problematic stretch of line west of Paddington. At the time, trains were experiencing costly delays, partly due to unreliable power supplies. An ARS compliant signalling power system detects faults, isolates the affected section of cable and reroutes the current, restoring the original configuration once the fault is repaired – helping to keep trains moving.

Network Rail asked Amey to produce detailed drawings for upgrading the signalling power systems at Crossrail sites along the route. The scope of the project rapidly expanded as the value of the new approach became clear, eventually extending to five stretches of line: Hayes to Southall, Southall to West Ealing, West Ealing to Acton, Acton to Ladbroke Grove, and Ladbroke Grove to Paddington.

It was an ambitious task with many challenges, one of which centred on the power modelling. Throughout the project, the team had used Amey’s own bespoke software, SPAM (signalling power analysis model), to simulate the operation of the circuits according to different loads and other variables. SPAM, a unique tool built from years of gathering accurate real-world data, has helped establish Amey as the industry leader in the earthing and bonding of signalling networks.

However, towards the end of the project Network Rail introduced a new modelling and simulation platform, ETAP (Electrical Transient Analyser Programme), as the standard for all its electrical power contractors. This meant the final analysis of the Crossrail ARS design had to be carried out in ETAP, which handles earthing requirements differently from SPAM. Fortunately, when the design data was input into ETAP, the output values were broadly the same, avoiding a potentially major problem.

Ultimately, the electrical engineering expertise and flexibility of the Amey designers, coupled with their ability to build close working relationships with the Network Rail and Crossrail teams on the ground, ensured the success of a project that significantly improved the reliability of the train service into Paddington.








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