The work is due to commence in January 2024 at Alstom’s Polmadie Depot.
The scope of work includes the overhaul of pneumatic and electrical components such as autocouplers, gangways, batteries, underframe air valves, cab HVAC and toilets.
The 40 Class 334 trains are currently on lease to ScotRail, operating on routes between Glasgow and Edinburgh.
The first unit, 334001, arrived at Shields Depot on 3rd August 1999.
A pair of 334 had a test trip to North Berwick, although they are not normally scheduled to be used on that route in passenger service.