The Glasgow Subway, or clockwork orange, as it's sometimes referred known, has carried generations of local commuters round its iconic loop.
But while the route hasn't shifted much, the subway has evolved significantly since it opened way back on December 14, 1896.
Here we take a look at how the world's third oldest underground railway system has changed over the decades.
READ MORE: The story of the only Glasgow Subway station that no longer exists, Merkland Street
The subway was originally a cable-hauled system propelled by stationary steam engines and was the first of its kind in the world.
The first major overhaul began in 1923, when the Glasgow Corporation Transport Department began the process of electrification.
There was then little change until the Greater Glasgow Passenger Transport Executive embarked on a major modernisation in 1977.
The subway was closed for this to take place and didn't reopen until April 16, 1980.
The Queen visited the revamped Buchanan Street station as part of the grand re-opening.
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Thirty-three 'power car' trains were introduced and separate flank platforms were added to six of the busier stations and twenty-eight sets of escalators were also provided.
A few years ago Strathclyde Partnership for Transport announced a £288 million modernisation project.
St Enoch, Hillhead, Partick, Ibrox, and Kelvinhall stations underwent full refurbishments, with other stations following suit.
It was also revealed that the Subway’s signalling equipment, control systems and control centre would all be replaced..
Modernisation of the subway continues, with the Glasgow line becoming the first in the UK to introduce driverless carriages.
A version of this article was first published in 2016.
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