There remains significant work to complete in key areas: the construction and fit-out of the tunnels and stations; and the testing of the signalling and other systems.
Construction and fit-out of the tunnels and stations:
• Work to fit-out tunnels with, for example, cabling and equipment needed to support signalling systems is not yet complete.
• Stations are in different states of completion and there is still significant work to be completed. Bond Street and Whitechapel stations have caused particular problems. Stations are not required to be fully completed in order for some services to start running but opening the railway without stopping at some unfinished stations will delay passengers receiving the full benefits of the railway, and significant further construction work could continue to delay testing.
Testing of the signalling and other systems:
• This includes the lineside signalling systems, the signalling equipment on the trains, as well as the station systems that remotely monitor and control systems, for example, ventilation.
• The software and infrastructure required to operate the complex signalling systems on trains and at the trackside has been significantly delayed. These systems are critical for the safe and efficient operations of services.
• Crossrail Ltd is adopting an incremental approach to the testing of trains running through tunnels, gradually increasing the number of trains tested on the central section, before beginning testing across the entire line. Crossrail Ltd does not yet know how long this testing will take.
Trial running and preparing for operations:
• Once the signalling and safety systems are complete and full testing has been carried out, the railway will be ready to be commissioned and handed over to the operator to begin trial running. This process allows operators to test how the service will work in practice, and refine areas such as passenger management, and how to address delays and faults when they occur.