However, when the line reached Glasgow, the operators of the Forth and Clyde Canal (at the time a direct competitor of the new railway line) refused to allow it to pass over the canal on a bridge. As a result, the railway had to tunnel under it, creating a slope that was too steep for early steam traction engines to be able to climb. The solution was to install powerful stationary engines at Cowlairs at the top of this slope to haul trains up it using a hemp rope.
Cont./