The Railway's original purpose was the movement of coal from nearby collieries to ships on the River Tyne. The oldest part, c1647, was the Lobley hill section. It had over 300 yers of coal traffic when closed in 1964. The surviving 1725 Sunniside to Causey section is now the worlds oldest working railway and the Causey to East Tanfield section dates from 1839./
Marley Hill engine shed built in 1854 , and in colliery use until 1970, is where the loco fleet is maintained. The shed is open to the public every day and has a special 'Santa Steamings' throughout the christmas period.