TfL has announced plans to close part of the Northern line for several months as it completes a huge upgrade of Bank tube station. The bank branch of the Northern line will close between mid-January 2022 and mid-May, and this is to allow a new train tunnel recently dug next to Bank station to be linked up with the existing train tunnel.

The Northern line will be closed between Moorgate and Kennington — which are the two closest locations on the line where trains can be reversed over a rail junction.

During the closure, more trains will run through the Charing Cross branch, and a new bus route will be added between Oval and the City. TfL is also working with Network Rail and other train operators on alternative travel options on national rail services with more detail to follow on this closer to the time.

All this work is needed to bring a huge upgrade at Bank station into use.

The upgrade will add an entirely new Northern line platform and tunnel to the station, while the existing southbound platform and tracks will be turned into a wide corridor to create more space for people to use the station. If you’ve used the southbound platform in the past couple of years and seen some odd doors on the “wrong” side of the tracks, these are the passageways that will link to the new southbound platform.

When completed, a new tunnel and travolator will link the Northern and Central lines and new escalators will link the DLR to the Northern line and direct up to street level. The project will also deliver two new lifts, improving accessibility to the Northern and DLR platforms. A new entrance will also be opened, a bit later in 2022, on Cannon Street with escalators and lifts directly down to the Northern and DLR platforms.

The closure of the bank branch of the Northern line was always expected to happen, as it’s part of the plans for the upgrade, but the date hadn’t been confirmed until now. Originally expected later this year it will now take place from 15th January to mid-May 2022.

During the closure, the Nothern line tunnels on either side of Bank station will be filled with soft concrete to stabilise them while tunnelers in the new tunnel dig through to the other side, linking the two tunnels together. Then they need to fit the tracks to join up the tunnels.

While that is going on, the old southbound platform will have its tracks filled in, and space levelled to create the wide concourse linking the Northern line to the new travolator and escalators.

The improvements at Bank will mean that there is 40 per cent more space within the station, as well as step-free access to the Northern line for the first time at Bank and improved access to the DLR.

When it reopens in May 2022, Bank tube station will look very different.