How a Rat derailed the train at Shahdara ?

One mishap to the Frontier Mail deserves mention if only for the unusual circumstances in which this crack train was derailed. In truth it was a RAT that caused a top-link driver to over-run signals at Shahdara Junction., the first stop on the way from Lahore to Lalamusa. The engine, SP/S class 4-4-0, had picked up two compos and backed them down on to the train at Lahore. All coupled up, the driver had 'created vacuum' and the guard, carrying out instructions, had duly tested the brakes by partially destroying the vacuum. With everything apparently in proper working order, the train had gone on its way. But at Shahdara, the driver after shutting off steam found to his amazement that he had hardly any brake power and did not even have time to reverse his engine and apply steam again before the train overshot the starter which was at danger, and the leading bogey-wheels of the engine ran off the rails at the end of a short catch spur to which the points had been correctly set...