The railway operates a passenger service every Sunday, plus other days, as well as occasional demonstration coal, goods and mixed trains.

The Tanfield Waggonway was built by the Grand Allies, an association of coal-owning families, including the Bowes, Liddells, Ords and Montagues, who joined together to overcome wayleave difficulties from about 1720.

Its purpose was to transport coal more reliably and cheaply from the inland collieries of County Durham to the staiths on the River Tyne at Redheugh.

Many older shorter coal waggonways existed to the north of the present heritage line, in the Whickham and Lobley Hill areas, but the Tanfield Waggonway was a much longer and heavily engineered route which gave the Grand Allies market dominance all year round.

The headshunt by Marley Hill signal box is the point where the west-east Bowes Railway crossed the south-north Tanfield branch.

[3] The early years of the railway as a preservation project concentrated on Marley Hill, preparing locos for steaming, working on the shed structure and acquiring basic needs such as water and electricity.

The first passenger train ran for a week August 1975, using locomotives No.21, No.32 and Sir Cecil A Cochrane, and a small carriage acquired from the British Steel Corporation site at Teesside.

[4] Part of the reason the line was preserved was the fact Marley Hill shed remained open until 1970.

[4] The current preserved line passes near to Causey Arch, the oldest surviving railway bridge in the world.