The railway which ran from Balerno to Princes Street Station and passed through Colinton opened on 1 August 1874. Colinton Station was situated where the access road and car park are currently. Both the tunnel and road bridge were built at the same time. Predominantly used for transporting goods to and from the mills on the water of Leith; passengers were also carried but this ceased on 30 October 1943. All services were withdrawn on 4 December 1967 as part of the Beeching cuts; the tunnel was closed and bricked up. In 1980, the Water of Leith Walkway was created. The tunnel re-opened as part of it, was painted and lighting installed. However, over time the painted walls deteriorated. In 2019 the lighting was changed to LED and work began on creating Scotland’s largest heritage mural. The tunnel is 140 metres long and all of it plus an extension to the outside wall at the Slateford end has been painted.

The lead artist is Chris Rutterford and he has worked with a team of professional and volunteer artists illustrating Robert Louis Stevenson’s poem From a Railway Carriage published in his 1885 book A Child’s Garden of Verses.

The poem runs along one side and on the other are many images linking it to local history.

More than 550 local people and groups including schools have contributed. Around 3% of the walls are still damp so some of the work was done elsewhere on marine plywood and then attached to the tunnel walls. The project has already brought more people to the local area and businesses and got rid of antisocial graffiti in the tunnel. There were quite a few dog walkers, joggers and others on the weekday we visited. We started at the Easter Hailes End near the carpark and walked through to the other end.

An event to celebrate the finished work was planned for September 2020 but of course the pandemic put a stop to that.