Work is underway on Crossrail, a major project to build new railway connections under central London.

The bulk of the Crossrail project is based around a new pair of east-west tunnels under central London connecting the Great Western Main Line near Paddington to the Great Eastern Main Line near Stratford. The tunnelled section of the project will be just over 13 miles in length and will be a difficult and expensive piece of civil engineering due to the extensive existing tunnelling in London and the city’s geology.

Each circular tunnel will have an internal diameter of 6 m (much larger than the 3.8 m diameter of existing tube lines) and as many as 65 new trains are planned to be constructed for use on Crossrail.

The project was initially proposed in 1989 by The Central London Rail Study, when it was clear that existing London transport services were running at capacity. Gordon Brown officially approved the project in October 2007.

The project is being managed by Cross London Rail Links Ltd (CLRL), a unique 50/50 Joint Venture company formed in 2001 which is now owned by Transport for London and the Department for Transport.

Completion is expected in 2017.