Heathrow Airtrack

From the longer Wikipedia page

Heathrow Airtrack is a proposed railway link in west London. The line as proposed by BAA, would have run from Heathrow Terminal 5 into central London and across the suburbs of south-west London. BAA announced that it was abandoning the project in April 2011. In October 2011 Wandsworth Council announced a revised plan called Airtrack-Lite.

The BAA proposal would have provided direct rail services from the airport to London Waterloo, Reading and Guildford, and offered an alternative route to the existing rail routes to Heathrow (namely Heathrow Express, Heathrow Connect and the Piccadilly line). The scheme, estimated to cost around £673 million,[2] was controversial mainly because of the projected impact on local road traffic due to the high number of level crossings on the route.[citation needed] In April 2011, BAA announced that it was abandoning the project,[3] citing the unavailability of government subsidy and other priorities for Heathrow,[4] such as linking to Crossrail and HS2.

Both proposals involve reopening a section of the former West Drayton to Staines Railway, roughly following the southern route of the line to a junction with the Staines to Windsor Line and a reinstatement of the Staines West chord