Pre-Owned 371-137 Class 31/6 (Refurbished) 31602 Network Rail LocomotivePre Owned Item, in as new condition. Test Run. History The British Rail Class 31 diesel locomotives, also known as the Brush Type 2 and originally as Class 30, were built by Brush Traction from 1957 62, numbering 263 locos. The Class 31 entered service in November 1957 and was one of the Pilot Scheme locomotives ordered by British Railways to replace steam traction. The class was originally allocated to the Eastern Region, but gradually became common