Glasgow was the third city in the world to open an underground transport system, after London and Budapest.

The 10.4km-long (6.5miles) twin track circular route was first opened as the Glasgow District Subway on 14 December, 1896.

However, a collision that day meant that it did not open again until five weeks later.

The subway trains were originally moved by gripping a continuous moving cable, which was moved by a coal-fired boiler in Scotland Street.

Train in red livery pre-1977 modernisation

The system has 15 stations, seven south of the Clyde and eight to the north, and a round trip took 40 minutes when the subway first opened.

The underground was originally built by the private sector, but financial difficulties meant that it passed into public ownership as part of Glasgow Corporation Transport in 1923.

The whole system was electrified in 1935 and two years later the name was officially changed to the Underground.

Passenger traffic on the system increased steadily, reaching a peak in 1949.

St Enoch station during modernisation

In 1977, with much of the rolling stock and infrastructure now 80 years old and passenger numbers falling, the system was closed for a massive �60m programme of modernisation.

After refurbishment of the stations, track, signalling and power supply, it was reopened by the Queen in 1980.

The new Underground also boasted a new fleet of trains in a vivid orange livery, giving rise to the nickname, The Clockwork Orange.

The new modern system boasted that the time for a complete circuit was reduced to 24 minutes, with trains every four minutes during the peaks.

Passenger numbers also began to rise again, doubling from 7.34 million journey per year before its closure to 14.7 million by 1994.