Crossrail is a 118-kilometre (73-mile) railway line under development in London and the home counties of Berkshire, Buckinghamshire and Essex. The central section and a large portion of the line, between Paddington in central London and Abbey Wood in the south-east, are due to open in December 2018; at that time the service will be named the Elizabeth line. The western section beyond Paddington, to Reading in Berkshire and Heathrow Airport, is due to enter operation in December 2019, completing the new east-west route across Greater London. Part of the eastern section, between Liverpool Street and Shenfield in Essex, was transferred to a precursor service called TfL Rail in 2015; this section will be connected to the central route through central London to Paddington in May 2019.
The project was approved in 2007 and construction began in 2009 on the central section of the line – a new tunnel through central London – and connections to existing lines that will become part of Crossrail. It is one of Europe's largest railway and infrastructure construction projects