The Elizabeth Line will be open to passengers from 24th May – just days before the Queen’s Platinum Jubilee weekend.
Transport for London (TfL) announced that the Abbey Wood to Paddington section of the Crossrail project will open after a series of successive delays.
It was due to open in December 2018 but the project has faced numerous setbacks.
The Elizabeth Line will link Reading and Essex via central London.
Once the route is open, services will run every five minutes between 06:30 BST and 23:00, although a full timetable will not be in place until May 2023.
The opening date is also subject to final safety approvals being agreed.
TfL said there would be a special Sunday service for the Platinum Jubilee weekend.
Previously, transport bosses would only commit to an opening date during the first half of 2022.
The project had an original budget of £14.8 billion, but the government pledged an extra £4 billion to help get it open.
The Elizabeth Line will run from Reading, west of London, to Abbey Wood and Shenfield in the East.
Here’s the full route map: