The two vehicles were delivered new to the ER in March 1957. Initially no depot was acknowledged, in June '57 40A (Lincoln) was shown as their home.
The Eastern Region allowed the set to be exhibited at a Rolls Royce Exhibition from 6th to 11th May 1957.
Testing occured in mid-'57 and included runs between Manchester Victoria and Rochdale, including the 1 in 27 Werneth incline. The two cars, which weighed 83 tons tare were loaded with 11 tons of brake blocks to simulate a complement of 200 passengers. The train was stopped on the incline and restarted without slipping, reaching a balancing speed of 14mph. Another series of trials were done between Carlisle and Skipton, without the load of brake blocks, but on several trips a tail load of 57 tons was attached and on one trip a dynometer car was added as well. With the tail load of 57 tons the unit was repeatedly started from rest without slipping on the 1 in 100 gradients and reached a balancing speed of 31mph. It then worked from Lincoln with the rest of the class.
A survey in 1965 looking at DMU allocations and operations showed 50000/56000 along with 50001-13/24-7/9-49 and trailers 56001-11/3/6/24-49 being allocated to 40A (Lincoln). The depot's sets worked the following services:
Considered non-standard, they were withdrawn in October 1967. They languished around Lincoln until moving to Stratford Works around June 1970. They were noted there on the 16th, still in lined green but in poor external condition with several windows missing. 50000 was receiving attention underneath at the time, probably removal of useful parts. It was outside the Works by the 20th. Next reported sighting was at Trowse sometime in 1972, before they went for disposal at A.King, Norwich in October 1972. The picture below is believed to be 56000 / 50000 awaiting disposal, taken by Tony Wilkins.