|50396||RDB||975089||DMBS||Rail Top "Trim" Lab Coach 5 - Track recording Car with 975090 (ex-56162)||4/71||3/90|
|50397||DB||975137||DMBS||CCE Viaduct Inspection Unit No.1. The departmental number was never carried by the vehicle.||2/71||7/78|
|56160||DB||975228||DTC||CCE Viaduct Inspection Unit||2/71||7/78|
|56162||RDB||975090||DTC||Rail Top "Trim" Lab Coach 5 - Track recording Car with 975090 (ex-50396)||4/71||3/90|
The Derby RTC Lab5 set was used by the Derby Railway Technical Centre mainly for developing new systems (though it was borrowed for operational duties from time to time). It was painted into their house colours of rail blue / red with yellow ends. Initially it retained it's route indicator box, this was later painted over. Its travels around the country included the only visit of a 103 to Scotland.
Edwin Marks notes "around 1989 someone graunched the gearbox and thereafter it had to be hauled usually by the Research Class 31 (though I think it was sometimes loco hauled before that)". After withdrawnal the set left Derby on the 12th February '91 for Mayer Parry at Snailwell. The same 9X14 working also included Class 116 53063/119 and Class 104 53451/529.
After 50397/56160 were withdrawn from Chester on 17/2/71 they were earmarked for service as a 'Viaduct Inspection Saloon' but departmental numbers were only carried on the DTC (noted at Penzance Depot as such on 31/7/72 & 9/8/73). The power car was painted all over yellow and labelled on each side "Chief Civil Engineer's Department Universal Viaduct Inspection Unit No.1". They appear to have been little used, if at all, and were stored at places such as Penzance, Plymouth, Harwich, Didcot and Old Oak Common before withdrawal in 1978. They were later preserved.
Sandite vehicle 56156 / 977047 was withdrawn from passenger use in February 1981 from Chester and continued in its new role until withdrawn again in June 1986.