Stadler has received an Sfr133.3m ($140.4m) contract from AB Transitio for the delivery of an additional 12 double-decker trains.
With this contract, Transitio has exercised its option from a contract signed in 2016.
According to the contract, the trains are expected to be delivered late next year and will operate in the Lake Mälaren region, west of Stockholm.
In 2016, Transitio and Stadler signed a contract for the delivery of double-decker trains for different parts of Sweden.
In the first call-off order, 33 trains were ordered for Mälab, following which eight additional trains were ordered for Uppsala Länstrafik.
Transitio has so far ordered 53 KISS trains from Stadler.
The four-car trains will include one class for comfort and are said to provide legroom for passengers.
The car bodies of the Mälab trains were modified for the Swedish clearance gauge.
The trains can operate at speeds up to 200km/h and feature double-walled car transitions, underfloor heating and strong insulation for adverse climates.
Stadler Sales head Ansgar Brockmeyer said: “Just like the trains that have already been in passenger service since December 2019, the newly ordered vehicles will correspond to the Scandinavian design line developed jointly with Transitio.
“The fact that we have received a follow-up order from Transitio so soon after the new double-decker trains started passenger operations is a great vote of confidence and recognition of the quality of the new trains.”
In 2016, Stadler received legal approval to proceed with the Skr3.5bn ($424.4m) order to supply 33 trains to Mälab. The agreement was signed by Stadler and Transitio.
During the same year, Nordic Investment Bank (NIB) and Transitio signed an Skr695m (€73m) loan agreement for 20 years to finance the acquisition of 33 new trains.