IT IS the third oldest underground metro system in the world and a source of affection for many Glaswegians.
But the Glasgow Subway is also a vital transport network relied upon by 40,000 passengers each day to get them across the city.
Several stations have already received facelifts as part of what is only the second major modernisation programme of the system since it opened in 1896.
The busiest stop, Buchanan Street, is the latest to be given an overhaul following the likes of St Enoch and Hillhead.
The £300 million project will eventually deliver driverless trains and glass screens installed at the side of platforms.
More than 100,000 Bramble cards have been issued to passengers - similar to the Oyster cards used on the London Underground - replacing the old paper ticket system.
The modernisation of Glasgow Subway continues to make significant progress, particularly at our city centre stationsSPT spokesperson
The Subway will close for four weeks in summer 2016 to allow major engineering works to be carried out.
Replacement bus services will be run between stations to allow commuters to make their normal journeys overground.
Engineers will work to replace the ramps and turnout sections of the system, which allow trains to switch between the outer and inner line and access the maintenance depot in Govan.
An SPT spokesperson said: “The modernisation of the Glasgow Subway continues to make significant progress, particularly at our city centre stations. The recently completed St Enoch station is now a vastly improved facility and the new iconic canopies have transformed this busy public space. Work on Buchanan Street station is currently underway and continues in accordance with the project plan.
“The introduction of the Bramble smartcard in our Subway has been hugely successful with now over 100,000 customer cards issued. The expansion of the scheme onto other modes is progressing well particularly with Abellio Scotrail were the ability to use the same card for rail and subway will roll out in the first half of 2016 when the ability to top up cards online will also be released.
“It will be necessary to suspend train services for four weeks at the commencement of the school holidays in summer 2016 when passenger numbers are at their lowest. There is no need for our passengers to take alternative arrangement as we have already communicated that SPT will be providing alternative travel solutions.”
The Scotsman reported in February that two shortlisted consortiums are competing for a contract worth about £200m to build the trains and automated signalling for the Subway.
The trains are expected to running by 2020 – the year before the Subway’s 125th birthday.
Glasgow Subway is unique as the six-mile circular system’s gauge – the distance between the rails – is 20cm narrower than standard.
The system is owned and operated by the Strathclyde Partnership for Transport (SPT), formerly Strathclyde Passenger Transport,