Some ordering details - in March '58 the BTC placed a £325,000 order with BUT, to provide engines, transmission and control equipment for 62 2-car sets (power / trailer sets 50938-87 / 56221-70, and power twin sets 50924-35 / 51561-72). In Feb '59 the BTC ordered equipment for nine power/trailer sets (51416-25 / 56271-9) from BUT, together with the equipment for seven ScR Cross-Country sets and Class 127s.
At the end of 1959 it was announced that BR workshops would build a another 50 2-car sets (these would be 51901-50 plus partners). These would be 21 power trailer set for Nottingham - Leicester GC services, and 29 power twins for Manchester Suburban services (18 sets) and North Wales (11 sets). While this information appeared in the Dec. '59 Railway Observer 51901-50 (50 vehicles) was actually ordered on the 20/3/59 (lot 30601) with driving trailers 56484-504 (21 vehicles - lot 30602), but the other partners, DMCs 52037-65 have an order date of 31/12/59 and a much later lot no., 30660. So it looks likely that in March 59 there were 50 power trailers ordered, but this was revised in Dec. '59 to change 29 of them to power twins.
Vehicle 51562 (DMC) was the 1,000th DMU car to be built by Derby. They held a short ceremony to celebrate the fact in Nov '59. It was also the 414th lightweight aluminium car to be built. The works manager, AE Bates congratulated representative staff members concerned with the railcar construction. A special booklet commemorating the event was produced, a couple of pages are shown here. The vehicle was preserved by the National Railway Museum.