Catch points were two very short lengths of parallel track curving away from the running line, and unconnected to any other line. They were always located at or near the bottom of an incline, because their purpose was to derail any 'runaways', i.e. any loose-coupled waggon(s) which had broken away from the train and were careering down the line back the way they had come. Sometimes catch points were fitted specifically to prevent collisions at, for example, sidings or by waggons smashing onto a main line. Note the semaphore signal: the small signal-arm and the short post indicate that this is a shunting signal.