The 70m-long four-car C30s, which are the first metro trains in Sweden to be equipped with air-conditioning, will accommodate up to 634 passengers, 140 of them seated, and will replace the ageing CX trains, which date from the 1970s. Two sets can be coupled together to form a 140m-long eight-car set.

Bombardier was awarded an SKr 5bn ($US 600m) contract in May 2013 to supply the initial batch of 96 C30 trains with an option for up to 80 additional sets, with all 96 trains in the initial build scheduled to be delivered by 2022.

The C30 has 24 doors and an open layout, with more space for standing travellers as well as more areas for prams and wheelchairs and screens with dynamic line maps and station views.

Accessibility is improved with spaces for wheelchairs, an adjustment to the height of the assistant phone and blind letter placement, and a high-contrast colour scheme to help visually impaired passengers.

With the completion of resignalling and the delivery of new trains, peak capacity on the Red Line will be increased from 24 to 30 trains per hour by 2021.