British Rail Class 231

The British Rail Class 231 is a class of eleven diesel-electric multiple units of the FLIRT family, which have been built for Transport for Wales by Swiss rolling stock manufacturer Stadler Rail. The first units entered service on 18 January 2023.

History

The previous Wales & Borders rail franchise operator, KeolisAmey Wales ordered the new trains. Although KeolisAmey was removed as the franchise operator and replaced by an operator of last resort Transport for Wales Rail, owned by the Welsh Government, the scheduled full fleet replacement continued.

The units began testing in Switzerland in July 2021 and in November 2021 the first two units were delivered to Cardiff Canton depot.

Operators

Transport for Wales

The Class 231 units are currently used for services on the Rhymney line and the Vale of Glamorgan Line. They mostly operate between Rhymney/Bargoed and Barry Island from Mondays to Saturdays, and between Rhymney/Caerphilly and Barry Island on Sundays.

Sometimes they operate on other valleys lines as well such as the Merthyr/Aberdare Lines, the City Line and the Treherbert Line.

It is expected that they will operate the following services from around late 2025 or early 2026:

Maesteg to/from Ebbw Vale Town via Cardiff
Newport to/from Ebbw Vale Town
Cardiff Central to/from Cheltenham Spa.

The official revenue launch of the Class 231 took place on 29 March 2023 at Caerphilly.

Technical details

Class 231 units have four passenger vehicles, along with a separate "Power Pack" vehicle at the centre of the unit that contains four diesel generator sets. The diesel generators comply with EU Stage V emissions regulations. All vehicles are linked by unpowered Jacobs bogies, while the outermost bogie at each end of each unit carries the traction motors.

As of October 2024, TfW are planning to convert their Class 231 units to hybrid units with pantographs (meaning they would become bi-mode units more like Class 755s), and have mobilised a project team to support the implementation of the conversion with Stadler.

Fleet details

Illustration

Named units

Unit 231001 is named Sultan. It was suggested by a local school as part of a competition run by TfW, and is named after a statue at Ystrad Mynach of the pit ponies used in the local coal mines.
Unit 231005 is named Gavin & Stacey. It was suggested by a local primary school that participated in the Christmas Event at Barry Island which is part of the final episode of Gavin and Stacey.