3rd Line Support for the Maintenance of the London Overground WestCAD & SSI Interlocking

This is a single source for the Third line support and maintenance contract for the WestCAD signalling control and display system (SCDS) and the Solid-State Interlocking (SSI) which were developed by and installed by Siemens Mobility Limited for signalling control on the London Overground Core Windrush Line (formerly East London Line). The contract will end on the 31st July 2026.

This contract undertakes 3rd line support should faults not be rectified locally across the line. Siemens provide a 24/7 diagnostic hotline, all operational spares, escalation of fault to expert if unable to resolve and the availability of system experts in hardware/software.

This is estimated to cost during this period is £135,000 (excluding VAT).