Light at the end of the tunnel

This was taken in the middle of the Innocent railway tunnel - it is over half a mile long and I walked through it and then back over the top. In fact walked for about 3 miles today and enjoyed it though sore. We then went to the Museum of Scotland to see the Mary Queen of Scots Exhibition. Really good except for some small historical inaccuracies but at least it was better than the Tudors!!

The innocent Railway or The Edinburgh and Dalkeith Railway was an early railway built to convey coal from pits in the vicinity of Dalkeith into the capital. It was a horse-operated line, with a terminus at St Leonards on the south side of Arthur's Seat.
Opened in stages from 1831, it was Edinburgh's first railway, and used the track gauge of 4 ft 6in, commonly used for mineral railways in Scotland. The entry into the terminus involved a passage through a tunnel on a rope-worked incline.
It was not planned for passengers, but a trader operated passenger services and they were surprisingly successful, and the company later operated them itself.
When intercity railways were being planned, the North British Railway wished to reach Carlisle from Edinburgh, and it purchased the Dalkeith line in 1845 to secure part of the route. The new owners altered the gauge to the standard 4 ft 8½in and laid stronger track for locomotive operation. Part of its main line became incorporated into the Waverley Route. Only a small section of the network remains open.