 Normally, as soon as a train was past a box's home signal, the signalman would telegraph 'line clear' to the preceding box.During foggy or snowy weather, however, when a train stopped at a station 'line clear' was not sent until the train had restarted, or been shunted into a siding.In good weather therefore a goods train being shunted into a siding at Abbots Ripton should have been protected against another train running into it by the Abbots Ripton 'home' and 'distant' signals ; in falling snow, the home and distant signals of the previous box should have given further protection and the fast train should always have been at least one full block away.