High Quality Content by WIKIPEDIA articles! The Chelsea–Hackney line (also known as Crossrail 2, sometimes the Chelney line or Hacksea line) is a safeguarded route for a possible underground railway from south-west to north-east London. The route in its modern form was first drawn up in the 1970s and is the highest-profile project not under construction, but it will not proceed before the completion of Crossrail 1 in 2018. During the early 2000s the plan was developed by Cross London Rail Links Ltd, the developers of Crossrail, and the line is therefore sometimes known as Crossrail 2 and expected to be a large gauge tunnel.