locomotive mistakenly accepted the signal that had been cleared for the DMU. On 15 June 1965, an empty stock train passed a colour light signal and two ground subsidiary signals at danger before colliding at slow speed with the leading coach of the approaching 15.57 Scarborough - Leeds Class 101. Both drivers and twelve passengers were injured. On 11 July 1967, A 101 working on the 10.11 Chester to Manchester Exchange service collided at a speed of approx. 20 mph with the rear of the 02.00 Margam to Carlisle Class 5 freight train which was standing at the Winwick Junction Down Fast Home signal. There were no injuries. On 16 February 1977, an express passenger train hauled by Class 55 locomotive 55 008 collided with a Class 101 diesel multiple unit operating an empty stock train after failing to stop at . One of the vehicles of the DMU overturned. The guard of the express was slightly injured. The cause of the accident was that the brakes on the carriages of the express had become isolated whilst the train was moving in a freak event. The train had struck an object on the track, which had caused a traction motor cover to come lose. This struck the handle of the brake isolating cock, closing it and thus separating the brakes between the locomotive and train. On 28 March 1983, the 20.58 Falkirk Grahamston to Glasgow Queen St. service collided with a van that was allowed to roll away and drop 40 feet into the cutting near Eastfield shed. Original TOPS classes When TOPS was originally introduced only the Driving Motor Brake Second (DMBS) and the Driving Motor Composite (with Lavatory) (DMCL) were classified as Class 101 (AEC engines) or Class 102 (Leyland engines). The Driving Trailer Composite (with Lavatory) (DTCL) were either Class 144 or Class 147. The Trailer Seconds (with Lavatory) (TSL) were Class 162, the Trailer Brake Second (with Lavatory) (TBSL) were Class 168 and the Trailer Composite (with Lavatory) (TCL) were Class 171. Later all the cars were reclassified, becoming Class 101. Preservation The Class 101 was one of the largest classes of first-generation DMUs and, partly thanks to their relatively late withdrawal from revenue-earning service, numerous vehicles have been preserved on heritage railways, including the Great Central Railway and the North Yorkshire Moors Railway. There are only three centre cars preserved: at the Ecclesbourne Valley Railway,