EPR000506 ENGLAND (1935). Camilatone Ltd Building off the Edgware Road, West Hendon, 1935

Fogmen were sent out in foggy weather to give extra warning to drivers when the signals were less visible. This was done by 'fog signals' or 'detonators' - small explosive charges - placed on the head of the rail and which exploded when crushed by the first wheel of the train. In front of the hut can be seen a small lever frame which allowed the detonators to be put on or off the track without the need for the fogman to go onto the track with the hazard that implied! There would also have been miniature signal(s) by the fogman repeating the position of the main signals so the fogman knew when to apply or remove the detonators.