Elsecar Heritage Railway runs on the former Elsecar Branch of the South Yorkshire Railway, which opened in 1850. The single track line ran from Mexborough to Elsecar via Cortonwood, crosssing the River Dearne and Dove Canal by lifting bridge. Used for the transport of mineral traffic it also served collieries, ironworks and other local businesses. Nowadays it's an added attraction for visitors to the excellent heritage centre. Thus far, about a mile of track has been re-laid following a pleasant wooded route alongside the adjacent canal. Their principal operating locomotive is 'Mardy Monster' Britain's most powerful industrial steam engine. She is a 'OQ' class 0-6-0ST with a remarkable tractive effort of 29,500 lbs., higher than many express passenger types. Built in June 1954 by Peckett & Co. of Bristol she was employed at Mardy Colliery in South Wales until 1976.