The Glasgow UndergroundD/Subway
Date/Time: November, 1950.
The Glasgow UndergrounD was originally known as the Glasgow Subway, and it was a cable-car system. That is, it operated similarly to the current San Francicso system, and to the ancient cable tram system in Edinburgh: two continuous cables, one for each direction, always in motion, driven by steam engines. Each car had a "gripper" which could grab on to the cable and pull the car along at a constant speed.
The route was roughly circular, and the cars just kept going around the loop. The river Clyde was crossed twice. At one point, the crown of the tunnel sticks up a little above the bed of the river. One day, one of the steamboats (known as "puffers") that service the outlying islands (run by MacBrayne, I think) tried to leave Glasgow at low tide, and hit the concrete. The next day, the headline in a local paper was "Puffer Stuck on Subway!".
That headline is on par with the sign on the freeway entering San Diego: "Cruise Ships Use Exit 12".
I believe the official name was changed to "Underground" when the line was electrified, about 1935.
The line still runs, with newer trains and improved stations. It still consists of two loops of track, one for each direction of travel.  Originally, the two loops were quite separate, with no connection between them: no switch points at all on the system. During the recent re-build of the system, a crossover was added. It took the drivers some time to get used to this innovation!
The 1935 electrification was quite bizarre. As well as a conductor rail for traction current, there was a completely separate pick-up system for lighting. On almost all electric rail systems, the lighting power is taken from the same source as the traction power. Indeed, at that time, Glasgow had a huge electric tramway system, and on each tram, the lights were powered, of course, from the traction circuit. However,  the subway already had a lighting system, installed for the cable-cars. This separate system was retained after the conversion even though it would need its own maintenance and upkeep, possibly because it meant that the lights on each car did NOT have to be re-wired for the higher (traction) voltage. Conductor rails for both circuits were on the side of the tunnel, part-way up the car on the side away from the platforms. This was only possible of course because there were no doors on that side of the car; and it was necessary for the lighting circuits as a between-the-rails current pick-up would have interfered with the traction cable.
The method used by the signalling system to detect the presence or passage of a train was even more bizarre, since it depended on that lighting circuit! This design decision was allegedly forced on designers because both running rails were mounted on steel cross-ties/sleepers, and so conventional track circuits could not be used. But even at that time, there had been other railways that had had rails fastened to steel decking - for example, the Liverpool Overhead Railway. Rubber gaskets or washers were already well-known as a means of insulating heavy equipment such as rails. A very curious decision.
There was a sort of treadle in the track for each section, which was pushed down by the wheelset of a train.  When a train entered a section it depressed the treadle, which was fixed to the rail just ahead of the signal. This changed the state of the section to 'Occupied', and set the signal to Danger. The lighting current was used (in connection with a short length of one of the lighting conductors or 'T-irons') to clear the section the train had just left. The 'clearing section' was a short length of T-iron approximately 600 feet beyond the signal, which, when the train passed and drew current from it, cleared the section. Thus a train with its lights out would leave the sections behind it in the 'Occupied' state as it went, and eventually it could fill the entire circle up with phantom trains
I first travelled on the line in 1938, though I have no memory of it. However, I did return on several occasions, and in 1950 I took these photos.
I would like to thank several people for sending me information about many of these pictures. Each person's contribution is flagged with a digit in brackets.
This page last updated 2006-01-19