 Silting of Pentewan Harbour had been a recurrent problem, limiting its attractiveness to shipping.In 1874 an Act of Parliament was obtained authorising the use of locomotive traction on the Pentewan line, and also extensions northwards into the china clay fields.This ambitious scheme changed the name of the owning company to the "St Austell and Pentewan Railway Harbour and Dock Company" with capital of £50,000.