The depot at Taff’s Well, six miles to the north of Cardiff, will also become the base for 400 train crew, 35 Metro vehicle maintenance staff and a South Wales Metro integrated control centre employing 52 staff.
Clearance and construction work for the new depot is expected to start in 2019 and complete by mid 2022.
Transport for Wales will procure construction companies for the new depot through Sell2Wales and the Stride framework to ensure that economic benefits for Wales are maximised.
As part of the Welsh Government’s £194m investment in Wales wide station improvements, Taffs Well will also see its railway station being modernised, with a park and ride facility to improve commuter access to the South Wales Metro.
The new depot at Taffs Well will complement existing South Wales depots including the one in Canton, which will benefit from around a £5m investment to modernise maintenance facilities.
There will also be investment in enhanced stabling facilities in Treherbert and Rhymney, and an upgrade of the station at Rhymney to accommodate more and longer tri-mode rolling stock.
Economy Secretary Ken Skates said: “The construction of the Taff’s Well depot presents one of the first opportunities for Welsh suppliers to directly benefit from our £738m investment in the South Wales Metro which will see us creating a sustainable and connected transport infrastructure.”