154001 passes Clay Mills (Hargate) on 15 May 1987 with the 11:06 Birmingham New Street to Derby Regional Railway service. This unit initially entered traffic in 1984 as 150002, one of a pair of Class 150 prototypes. 150001 was fitted with Cummins engines and Voith transmissions, and 150002 was equipped with Rolls Royce engines and transmissions by Self Changing Gears. Unfortunately this latter combination proved to be less than reliable, and in early 1987 150002 was converted into a testbed for the forthcoming Class 158 units, complete with Cummins engines. It was renumbered 154001, and spent the next five years in this guise, before being converted back to a standard Class 150. It shouldn't really have been a surprise that the Rolls Royce engines would be unreliable, as the earlier Class 111s were always having problems.