A 6-car Trans-Pennine DMU travelling from Leeds (City) to Liverpool (Lime Street) was approaching Bold Colliery Sidings at 50 m.p.h. under clear signals when it became derailed over facing points, the leading bogie continuing down the main line whilst the remainder of the train became derailed to the left into a colliery reception siding. The train came to rest 270 yards beyond the facing points. Structural damage to the train was slight although underframe equipment was badly damaged.
The accident was a result of the switch blades having been standing agape when the leading wheels of the train passed over them, despite the trailing end of the crossing being set and locked as normal. This may have been the result of a failure during testing of the points by the Signalman or a short-lived false feed to the points machine after the test had taken place. Had the facing points failed during the testing procedure or been much slower in operation than the trailing points, the Signalman may have placed the lever fully normal (cutting off the power supply) as soon as the No 30A (trailing) points had moved to and been proved normal but while the No 30B (facing) points were still short of half stroke. With the crossover falsely detected, the Signalman would then be able to pull off the Home signal even though the facing points that it was protecting were standing open. It was possible that this was in itself brought about by a fixing screw being inserted sideways through the lid of the timber box covering the point mechanism so as to fret the wires inside it.
MOT; b/c; 11pp; f/o location diagram, general layout diagram, detailed layout diagram, gradient diagram; f/o circuit diagram of No. 30 Crossover; p/o overlay trace for circuit diagram of No. 30 Crossover (J.R.H. Robertson).
Bold Colliery, LMR
Involving Class 124
Information from Peter Mullen