Falkirk Tunnel

In Falkirk to do more geocaching. I was recommended to find this cache in this tunnel. 

The tunnel , was created nearly 200 years ago and was originally used for transporting coal.  Today it carries the Union Canal beneath Prospect Hill in Falkirk and connects Falkirk to Edinburgh. The Falkirk Tunnel is approximately 630 meters long, 18ft-wide, 19ft-high and has a 5ft-wide towpath.

I needed to find a clue at each end of the tunnel before the cache could be found somewhere in between.