Julien Michel of railcolornews.com said:
[UK] Transport for Wales: meet the fleet
While none of them have emerged from the factories yet, and while the only preview we have of Transport for Wales’ future trains is in the form of artist’s impressions, the national transport authority has released the class numbers of the new fleet, so we can now call the trains by their names.
Operated by KeolisAmey, the new-build train fleet (that excludes existing rolling stock transferred from other operators and the Vivarail Class 230 DEMUs built by transforming former London Underground D-Stock trains) will be formed of the following.
Class 197
The Welsh-built Civity UK DMUs, a CAF product, will serve the entire Transport for Wales network, and will be designated Class 197, following the two previous Civity UK DMU classes, 195 (operated by Northern) and 196 (being built for West Midlands Railway).
Class 231
The Stadler Flirt DEMUs, which will operate on the Ebbw Vale, Maesteg, and Cardiff-Cheltenham lines, will be designated as Class 231. These will feature the Stadler “signature” power-pack car, which holds the diesel engine equipment, as found on Greater Anglia’s Class 755 Flirt BMUs.
Class 398
398 is the class number chosen to designate the Stadler-built Citylink tram-trains. This number was chosen as a reverse-follow-up to the existing Class 399 tram-trains, which are also Citylinks but built at the time when this was a Vossloh product, before Stadler bought out part of Vossloh.
These Class 398 tram-trains will stretch their wheels on the Treherbert, Aberdare, and Merthyr lines.
Class 756
Stadler will also build Stadler Flirt TMUs (tri-mode multiple units: diesel, overhead electric, battery electric) for the Rhymney, Coryton, and Vale of Glamorgan lines. These will be known as Class 756s.
This new fleet will enter service in 2022-2023.