NM6985 : Borrodale viaduct
The original plan was to built a concrete viaduct over the burn similar to others on the line however when the laird was approached he insisted that the piers be clad in granite. This would have been too expensive so this single 127' 6" span in concrete was built. It may well have been the largest in the world at the time but in fact there were only five others anywhere in the world all of which carried only light road traffic so it was a remarkable engineering feat.