Some trailers were withdrawn through old age, with 2-car sets appearing, and some sets ran with Met Camm trailers during the '80s. While most Derby sets stuck to 3 cars, one set was increased to 4 cars in 1984 for heavily loaded commuter trains on the Matlock line.

By 1985 the age of the Derby fleet and the continual pressures to cut costs and reduce overtime working were causing decreasing standards of reliability. The Sprinters were being delivered to Derby with a changeover date of January 1986, so only preventative maintenance was carried out. Windows and seats were patched with tape. There were jammed droplights, and lack of heat and lights became common, and breakdowns increased.

However the Sprinters encountered teething problems, requiring other 1st generation sets to be loaned from Tyseley, Chester, NH, Lincoln, Hull and Norwich. As sprinter availability improved, most of the loaned sets were returned by Sat. 18th Jan 1986. That weekend saw the last 120 working to Matlock, and also the first in several months, when the booked driver had not yet been trained on Sprinters so a 120 had to be hastily summoned for the 14:20 and 15:00 return.

By mid-February '86 most 120s had left Derby, some to Chester for conversion to DPUs, some to Ayr and the rest (ten 3-car sets) to Tyseley for use during "Operation Proof House" before continuing to Ayr, although the intention had been to withdraw them on complation of the remodelling work. The Chester and Newton Heath sets were also due for withdrawal with the delivery of more Sprinters, but problems with the ScR's ailing DMU fleet in the run up to the Ayr line electrification meant that any surplus DMU sets that could be run were transferred to Ayr. This included 120s from all three LMR depots, and the last two sets from Cardiff. In Sep '86 the Ayr 120s were reallocated to HA for use on the Dundee services, although in reality they were used on most Scotrail DMU services.

The last seven cars (3 DMSLs & 4 DMBCs) only survived due to being asbestos stripped in the early '80s.

Last withdrawn were 50658 / 50699 / 50732 / 50733 in October 1989.