Crossrail 2

Crossrail 2 is a suspended proposal for a hybrid commuter rail and rapid transit route in South East England, running from nine stations in Surrey to three in Hertfordshire, providing a new North–South rail link across Greater London. It would connect the South West Main Line to the West Anglia Main Line, via Victoria and King's Cross St Pancras. The intent was to alleviate severe overcrowding that would otherwise occur on commuter rail routes into Central London. When first proposed, the hope was for construction to start around 2023, with the new line opening from the early 2030s. The project's cost has been estimated at £31.2 billion.

The line would have been the fourth major rail project in the capital since 2000 (East London line extensions opened in May 2010, the Thameslink Programme opened in 2018 and Crossrail opened in May 2022). National Rail's projections of overcrowding, including in suburbs and tourist destinations less well-served by the Underground, led it to call for more new lines and cross-London line proposals gained more importance with Euston being named as the terminus of the planned High Speed 2 rail line.

The scheme was shelved as part of the conditions for emergency COVID-19 funding worth £1.8 billion between the government and Transport for London (TfL) announced on 1 November 2020.

The project was earlier known as the Chelsea–Hackney line (or Chelney line) in reference to a potential route. The plan for a line on this alignment has existed in various forms since 1970, initially as an Underground service and later as a standard railway.