The Cronk and Harwick Railway was a railway that ran from Harwick to a quarry near Cregwir. It also had a branch to Ballaswein. Little is known about the railway, but it appears on some Island of Sodor maps.
After the final suppression of the "Trade" in the mid 19th century, great poverty came to the Ooyre Valley, but by the 1850's it was hoped that a railway - The Cronk and Harwick - would provide honest work and help to solve the problem. A fine new pier was built with stone quarried in the valley and some 12 miles of track were laid as far as Cregwir before the money ran out. The line was horse worked and though this and other quarries remained in production until the 1950's, the railway had long since worn out. It was shown as still in being, but abandoned, on several maps; but it had actually been pulled up for scrap in 1943, during the Second World War.