In the workshop of the Vale of Rheidol Railway is the Baldwin built Class 10-12-D # 794 of the Welsh Highland Heritage Railway undergoing contract restoration. This 4-6-0 T pannier tank engine was built 1916/1917 for the British War Office, together with 494 sisters. When the Great War broke out in August 1914 the French lost most of their locomotive building capacity in the Northern France to German occupied area. Therefore, the French Army demanded fast replacement of the locomotive building capacity for their useful 2′C n2t type which had proved to be a reliable locomotive type for the lightly laid military railways.Three steam locomotive type drawings were sent to Baldwin Works (finance guaranteed by the French Government) for production of C n2t, 2′C n2t, and light Mallet B′B n4v for 600 mm (1 ft 11 5⁄8 in) gauge lines. With the usual American liberty, Baldwin Drawing Office produced their "version Americaine" of these locomotive types. The first C n2t (based to Decauville design) came out in November 1914 and the first batch of 2′C n2t in January 1915. Only two more batches were built for the French. The British War Office decided to adopt the type as its principal military steam locomotive, and Baldwin started production in 1916, building 495 locomotives between October 1916 and April 1917. All were delivered except for nine which were lost at sea. After WW I many of this locomotives were exported to India. # 794 was repatriated in 1985 for the Imperial War Museum. It will carry the number "590" in future, being almost identical to the original WHR locomotive of that number, running in black paint scheme for the Welsh Highland Heritage Railway (WHHR), on long term loan of the Imperial War Museum.