A tunnel at King’s Cross station that was closed in the 1970s has been reopened, with the first trains passing through just before 5am this morning.

The final approach to King’s Cross station is through tunnels, and three double-track tunnels were built, but in 1977, the station was redesigned with a new layout between the tunnels and the platforms and the introduction of bi-directional working in the tunnels, so they closed one of the three tunnels as surplus to requirements.

However, with passenger numbers rising — in pre-pandemic times — and likely to eventually return to their pre-pandemic numbers, the station needs more capacity. Not so much in the station itself, but in the approach tunnels, which are a capacity bottleneck.

A major project to reopen the closed tunnel is being carried out along with a simplification of the track layout to improve reliability.

That work has been going on now for over a year, with new track layouts, signalling and preparing the tunnel for reopening. At the weekend, the signalling upgrade was completed with the handover from the old signal box to the York-based rail operating centre.

This morning, the old tunnel reopened, and trains from LNER and Great Northern made a synchronised arrival at King’s Cross.

A moment of history! After 40yrs of closure, the Eastern bore reopens @NetworkRailKGX. @GNRailUK & @LNER arriving together in true industry collaboration! pic.twitter.com/GMbJTph8KW

— Ricky Barsby (@RickyBarsby) April 26, 2021

At part of the wider works, Platforms 0-6 had been closed, but they have reopened today, while Platforms 7-11 have closed to allow the rest of the track layout to be realigned.

When combined with upgrades elsewhere on the route, the East Coast Upgrade will also deliver capacity for operators to run more trains, adding an extra 10,000 seats every day. Apart from increasing capacity on the line, the cleaned-up layout allows the new Azuma fleet to utilise its increased acceleration when leaving the station so journeys can be slightly quicker.

The works at King’s Cross are expected to be completed at the end of this year.