The Tanfield Railway is a 4 ft 8+1⁄2 in (1,435 mm) standard gauge heritage railway in Gateshead and County Durham, England. Running on part of a former horse-drawn colliery wooden waggonway, later rope & horse, lastly rope & loco railway. It operates preserved industrial steam locomotives. The railway operates a passenger service every Sunday, plus other days, as well as occasional demonstration coal, goods and mixed trains. The line runs 3 miles (4.8 km) between a southern terminus at East Tanfield, Durham, to a northern terminus at Sunniside, Gateshead. Another station, Andrews House, is situated near the Marley Hill engine shed. A halt also serves the historic site of the Causey Arch. The railway claims it is "the world's oldest railway" because it runs on a section dating from 1725, ot