The limestone industry was also significant in Froghall. At the nearby Froghall Wharf, limestone was loaded onto canal narrow boats or burnt in lime kilns and then transported to the Potteries or further afield. The limestone was mined in the huge quarries at Caldon Low and then loaded onto an inclined tramway to Froghall. Four tramways were built and parts of them are still tracable in the landscape including various bridges and inclines. The final tramway, built by James Trubshaw was the most significant and involved the most engineering. Trubshaw's tunnel near Windy Harbour is an excellent relic of this fourth route.