On May 3, 2018 the city announced it would be purchasing seven new Stadler FLIRT (Fast Light Innovative Regional Train) trains to be used on the Trillium Line after the completion of the Stage 2 upgrades. The new trains will be double the length of the existing LINTs and have approximately double the capacity. These trains will be used in a mixed fleet alongside the existing Alstom LINTs. During normal operations, six FLIRTs and one coupled pair of LINTs will operate on the mainline with one FLIRT kept as a spare. Due to their length, these trains can not be used on the Airport Spur as the platforms on the spur can only accommodate the shorter LINT trains.
The FLIRTs are driven by electric traction motors with power provided by the "Power Pack". The Power Pack is a special car located in the middle of each trainset that can contain up to 4 diesel generators which provide the electricity used to drive the train. Because of this diesel-electric design, when the Trillium Line is eventually electrified, the FLIRTs can be easily converted to fully electric trains by removing the Power Pack car and installing pantographs.
The trains will feature a total of 16 doors (8 on each side) with two doors per car. Each door will be equipped with a button to open them as with previous Trillium Line trains. The addition of another door on each car will greatly improve passenger flow in and out of the trains compared to the existing LINTs. Between each of the pairs of doors, there will be a large multi-user area on one side, allowing mobility aids as well as bicycles to be placed. There will also be more grab bars placed to provide better help and support to all standing passengers.
Like with all past Trillium Line vehicles, the FLIRTs will feature a spacious, low floor interior. Passengers will be able to walk from one end of the train to the other through articulated gangways (including through the Power Pack).
The trains will be partially built in Switzerland and are currently planned to be assembled in Ottawa. The FLIRT trains are anticipated to begin service in the Fall of 2021 following the completion of Stage 2.
The video above is of the same model of train that will be received in Ottawa, but operating in Texas for TEXRail, during train tests and trials. Note that the TEXRail train only has a single pair of doors per car, while the trains in Ottawa will have two pairs of doors per car. You can also see the diesel Power Pack unit located in the middle of the train.
Below is a technical document on the TEXRail FLIRT trains.