As part of the preparations for the new Piccadilly line trains due to start carrying passengers from 2025, several tube train depots need to be upgraded to handle the new trains.
The introduction of the new fleet of trains requires changes to the maintenance procedures and facilities at the two sites of Cockfosters and Northfields depots, together with changes to several stabling berths including the expansion of stabling at South Harrow sidings.
The largest amount of work is needed at Cockfosters, which requires the demolition of the existing depot and cleaning shed, and train wash, and then the construction of a new combined maintenance and cleaning shed, train wash, wheel lathe, new internal access road, car parking, and associated works.
A planning application for the depot works was filed with Enfield Council last week.
The depot sheds being demolished were designed by the Charles Holden Architectural Practice, but have been assessed as having low historic value, being described as “utilitarian with low architectural or historic interest”.
As the depot is still serving the existing trains, it needs to be kept in action during the works, so the plans are to build the new buildings, then demolish the old, before then realigning the tracks for the new trains. The depot sits just in front of Cockfosters station, but there is a separate railway that runs around the side of the depot, so there’s unlikely to be any need to close the station for any reason during the depot works.
Works to build the maintenance and cleaning shed are expected to start in early 2022 and last around 28 months
Elsewhere, at South Harrow, work is already underway to build 6 longer stabling berths. At the moment, trains can only leave the Harrow depot heading northwards, so the works will also add a new southern connection onto the Piccadilly line. Work to upgrade Northfields Depot with a new stabling shed and additional stabling berths is expected to start later this year.