Class 123 Swindon 4-car DMUs

Introduced: 1963
Coupling code: Blue Square
Underframe: 64ft 6in
Engines: Leyland Albion 230hp
Transmission: Mechanical

These were the final batch of "First Generation" diesel multiple units and were built by BR Swindon. As with the first DMUs it built back in 1956 they were designated as "Inter-City" sets. They also had as much in common with BR standard coaching stock as they did with other DMUs having long underframes, buckeye couplings, Pullman gangways, BR4 bogies, oval coach buffers and interior finishes based on hauled stock.

There were ten four-car sets, five with a buffet, five without. Gangways at the outer ends of the sets allowed a buffet set to be attached to a non-buffet set giving access throughout. A set had seating for 24 first class and either 144 or 176 second class depending on whether it was one of the five buffet sets.

The sets were introduced on Western Region services between Swansea, Cardiff, Birmingham, Derby and Crewe, and on the Cardiff to Bristol route. Displacement saw them allocated to Reading for working "outer-suburban" services out of Paddington to Oxford and Newbury. Next stop was Cardiff for working secondary services from South Wales, such as to Bristol. In 1977 they were displaced again, but this time to store at Barry, as the Western Region had no further use for them. In June 1977 they were transferred on the to Hull Botanic Gardens and integrated with similar Trans-Pennine Class 124's on the "South Trans-Pennine" route from Hull - Doncaster - Sheffield - Manchester, and occasionally to Leeds.

Last withdrawals were in 1984 and none survive.