Crossrail will run 118 km from Maidenhead and Heathrow in the west, through new twin-bore 21 km tunnels under Central London out to Shenfield and Abbey Wood in the east, joining the Great Western and Great Eastern railway networks.

Crossrail will make travelling in the area easier and quicker and reduce crowding on London's transport network. It will operate with main line size trains, carrying more than 1500 passengers in each train.

It will deliver substantial economic benefits in London and the South-East and across the UK, linking Heathrow Airport, the West End, City and Canary Wharf via direct services. The estimated benefit of Crossrail to the UK economy is at least £36 billion (TfL figures, May 2006).

Royal Assent was given to the Crossrail Act in July 2008 and this gives the authority for the railway to be built.

In December 2008 the Government and the Mayor of London signed the key funding agreements for Crossrail.

Preliminary works commenced in early 2009 with main construction starting in 2010.

Crossrail will commence passenger services in 2017.