What must be the most advanced industrial steam locomotive design ever built in this country: three locomotives, Works Numbers 2994-6, designed and built in 1950 to the requirements of the Steel Company of Wales for use at their Abbey, Margam and Port Talbot works. The specification laid down that they were to embody every conceivable modem refinement and labour-saving device, as they were to be evaluated against diesels to decide the future railway motive-power policy. In addition, they were required to haul five loaded slag ladles, 65 tons each, up a 1-in-100 incline and round 2 1/2 chain radius curves. To fulfil these requirements 18" X 26" cylinders were fitted, together with piston valves, roller-type big-end and side-rod bearings, manganese steel axle-box and horn plate liners, hopper ashpans, self-cleaning smokeboxes, rocking grates and Lambets wet sanding. Steel fireboxes were used as well as "Owens" patent poppet valve and balanced regulator valves. Bagnalls had the sole manufacuring rights for these and they were often fitted, as well as being supplied to other builders.
The three locomotives were given the Running Nos. 401-3 and, although they proved capable of all they were intended to do and more, they were replaced by diesels in 1957. Works Numbers 2994 and 2996 were sold in September of that year to the Austin Motor Co. Ltd., of Longbridge, Birmingham. Works Number 2995 went to the N.C.B. in South Wales, and was scrapped in 1967. The locos 2994 & 2996 received the names Vulcan and Victor respectively but were sold on to the West Somerset Railway and were used to kick-start that preserved railway's steam services. Once Great Western locos became available for rostas, the Bagnalls became surplus. The Stephenson Railway Museum purchased 2994 and repainted it from "Kermit the frog" green to a black livery similar to a NER style. It remained in regular use until 2009 when it was placed on static display to await funds for restoration to the firebox/boiler.