As part of the Crossrail project, two platforms at Liverpool Street station have been lengthened, and one platform was taken out of action entirely.
At the moment, the future Elizabeth line trains that run between Liverpool Street and Shenfield are 7-carriages long, but to extend them to the full 9-carriages required two platforms to be lengthened.
When the Elizabeth line is fully open, trains will mainly use the new underground platforms, but there will be a four trains per hour service between Gidea Park and Liverpool Street in the rush hours, and those will use the mainline station platforms.
Platforms 16 and 17 have now been lengthened, with the final works carried out over Easter. In order to fit the longer platforms in though, the neighbouring platform 18 had to be decommissioned entirely as the tracks leading to it were cut by the longer platform.
The works, which included modular platform extensions, slab track installation, roof-mounted OLE and multidisciplinary design were carried out by BCM.
In related news, Network Rail also replaced worn-out timber sleepers on platforms 13 and 14, so they can now support 12 carriage trains instead of the previous limit on 8 carriage trains.