Glasgow Subway back in time: Over 125 years of history in 22 pictures

The Glasgow Subway is the world's third oldest underground system

As Glasgow's Subway gets set to celebrate its 127th birthday in just over a week, we've taken a look back through the archive at the changing face of the underground.

The double-track circular line has never been expanded even though plans have previously been examined with the tracks having carried millions of passengers through the years making the system an integral part of Glasgow's history.

It is one of the easiest ways to get around the city as there is only two minutes between each stop and unlike London’s underground, it’s not as easy to get lost as if you stay on the train for long enough, you’ll eventually reach your destination.  One of the most popular ways to explore Glasgow's Subway nowadays is to go on a 'sub crawl' where you can also sample some of the pubs located near to the stations.

Take a drip down memory lane on Glasgow's clockwork orange.