The cost of the east–west scheme including rolling stock was estimated at £885 million. A more ambitious proposal named "Superlink" was proposed in 2004, at an estimated cost of £13 billion, including additional infrastructure work outside London: in addition to Crossrail's east– west tunnel, lines would connect towns including Cambridge, Ipswich, Southend-on-Sea, Pitsea, Reading, Basingstoke and Northampton.
Both the Labour and Conservative parties made commitments in their manifestos for the 2010 election to deliver the railway, and the coalition government formed after the election also committed to the project.
Due to the size and positioning of the new platforms, Farringdon station will also be connected to Barbican station, and Liverpool Street to Moorgate station.
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, when it will be named the Elizabeth line in honour of Queen Elizabeth II.
Part of the eastern section, between Liverpool Street and Shenfield in Essex, was transferred to a precursor service called Tf L Rail in 2015; this section will be connected to the core route through central London to Paddington from May 2019.
The western section, from Paddington to Heathrow Airport and Reading in Berkshire, is due to open in December 2019, completing the new east–west route across London and providing a new high-frequency commuter and suburban passenger service.
The project was approved in 2007 and construction began in 2009 on the central section and connections to existing lines that will become part of the route.
An almost entirely new line will branch from the main line at Whitechapel to Canary Wharf, crossing under the River Thames, with a new station at Woolwich and finally connecting with the North Kent Line at the Abbey Wood terminus.
One branch runs to Heathrow Central (for Terminals 2 and 3), Heathrow Terminal 4 and Heathrow Terminal 5, The main western section runs on the surface from Reading to Acton Main Line.