While the basic working week has remained the same - 39 hours - signal modernisation and more and faster trains have meant that the job has become much more complicated and pressurised.
Bobby (not his real name) says: 'When I started it was a very simple . . . job of pulling levers and answering bell signals.' At that time a signalman might control 300 yards of track - all that you could see out of the signalbox window - or one junction.
Now, with computerised consoles and electronic signalling technology, a signalman can control 15 miles or more of track, dozens of junctions and up to 15 trains simultaneously travelling at high speeds in different directions. 'The pace of the job has changed beyond belief,' he says. 'It has got much faster. With so many trains to look after at the same time you really have got to be on your toes, you cannot afford to relax. A simple mistake by a signalman can actually slow down the movement of trains tremendously and cause severe disruption.
'Signalmen are basically in the front line on the safety issue and any signalman who makes any kind of a mistake, they are down on them like a ton of bricks.'
With night shift allowances, a middle grade signalman earning a basic pounds 169 a week might expect to gross pounds 280 a week two weeks in three before stoppages for tax, national insurance and pension.