The Stratford Box is sited on 52ha of railway lands in east London; the 1,073m long, 50m wide and up to 22m deep structure being built as part of the Channel Tunnel Rail Link to house Stratford International Station ( GE November 2001).
The length of the Stratford box is also designed to provide a crossover area for the high speed trains to change from one line to another, to allow greater flexibility to services in adjacent tunnels. An underground crossover, such as that in the Channel Tunnel, would have been difficult to construct and costly.
Construction began at its western end in July 2001 and at the eastern end in September 2001, with two teams working towards the centre.
Completion of the box ends is critical to allow tunnel boring machines to be lowered in to start work on the its tunnelled links on contract 220 and 240 while its remainder is built.
The box ends are due to be handed over in May this year, with excavation of the central section due to be finished in 2003.
The land raise is programmed to be finished by October 2005 with trains due to be running by 2007.