Pre-series deliveries of the newly-refurbished trains is due to start in mid-2020, and will continue until mid-2024.

The EMUs were designed and built by Bombardier 20 years ago, with more than 100 of the trains currently operating across Sweden.

In addition to undertaking heavy maintenance on the 54 two-car trains and five three-car trains, Bombardier will also be involved in technical and comfort upgrades such as changing carpets, repainting the exterior, refurbishing the seats and interior lighting, and installing additional pantographs with control equipment and new headlights.