I too was in Glasgow in the years before it closed; thought I had written about it here before but seems not. The tunnels actually passed under the street where I lived near Hillhead. the stations are unrecognisable nowadays from then, the 1970s refurbishment was very thorough, although the architectural standard is extremely basic.
The ticketing was novel. Every station had a small manned ticket office which issued tickets from a similar machine to those at cinemas where they push forward across a small counter. Cars in the two coach sets had doors front and back. When you travelled, on exiting the guard stepped onto the platform at the midpoint and held out two hands to collect tickets from those from the back of the first car and the front of the second. The platform porter collected those at the rear, and those exiting at the front had to give tickets to the driver. Aslef would have had a fit!
There was just one train which had three cars, done as an experiment and just carried on, and that ran with a second guard because of the additional door.
By the end the wooden bodies were seriously dilapadated and the longitudinal seats could be seen to be coming away from the bodysides as the trains lurched along. I wouldn't be surprised to be told that the glass fell out of the windows occasionally.
There were no points at all, the depot was astride the tunnels at Ibrox with a big open shaft, and there was a large hoist which lifted the cars out and placed them on stub tracks up above. I don't know if there was space for them all, as otherwise the cars were stabled overnight in a long line in the tunnels either side of the depot. Service was necessarily at the same intervals all day long, but on Sundays was reduced, so on Saturday night several units were hoisted out, and on Sunday night put back down. The staff were well skilled in this and apparently (I never saw it) only took a couple of minuted to do so. If a car developed a defect in the day they could similarly be replaced by another in very short order, necessary of course if the trains behind were not to back up. I seem to recall there were about 11 trains on each circle on weekdays, and maybe 7 each circle on Sundays.
Signals were automatic 2-aspect, and signal sections were station to station. Trains didn't depart until the one in front had cleared the station platform ahead.
A lot of the staff at all grades seemed to be close to retirement by the 1970s, and I believe many had come from the tramways when they closed down, it being a somewhat easier environment than on buses. Being Glasgow, there were some oddball moments. A platform porter once sidled up to me waiting on an otherwise deserted platform at Kelvinbridge and just announced "Y'know, son, collie dogs are the best ...". I still don't know whether this was code for something!
Do I recall that the front motor unit was smoking, and the rear trailer was non-smoking?
one thing that sticks in my mind was the no spitting signs
Exactly the same was still above the front upstairs windows inside all Glasgow buses at the time.