:You have to remember this route was built in the early 1840s, less than 15 years after the Rainhill Trials, it was not planned to carry the tonnages of coal that it saw fifty years later. You must also consider the geography (both ends of the tunnel are about 20 minute drive away from home). Both at Dunford Bridge and Woodhead the line is only a few feet above the level of the rivers (River Don and River Etherow, respectively).