The Somerset Coal Canal was built in the early 19th century to reduce the cost of transportation of coal and other heavy produce. The first 16 kilometres (10 mi), running from a junction with the Kennet and Avon Canal, along the Cam valley, to a terminal basin at Paulton, were in use by 1805, together with several tramways. A planned 11.7 km (7.3 mi) branch to Midford was never built, but in 1815 a tramway was laid along its towing path. In 1871 the tramway was purchased by the Somerset and Dorset Joint Railway (S&DJR), and operated until the 1950s.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): What was never built
A planned 11.7 km (7.3 mi) branch to Midford was never built