GTR awarded Siemens a £200m contract to supply 25 six-car trains in February 2016 after securing finance for the order from Rock Rail Moorgate, a joint venture between Rock Rail Holdings and Aberdeen Standard Investments.
The fleet will cover 21 diagrams encompassing services from London Moorgate to Welwyn Garden City, Hertford, Stevenage and Letchworth. The trains will replace class 313 EMUs built in the 1970s, offering a 27% increase in fleet capacity.
So far construction of 13 sets has been completed at Siemens’ Krefeld plant, with 12 trains currently at Wildenrath for testing.
The class 717s will enter service between autumn 2018 and spring 2019. Two class 313 sets will go off lease for each class 717 delivery.