The railway proper opened in 1725 and carried coal about 8 miles from Tanfield and Marley Hill to the coal staithes at Dunston, partly via gravity operated inclines. The line was incorporated into the Brandling Junction Railway during the 19th. C and eventually became linked to the entire rail network as this grew over the years, although it remained for coal use only and never carried passenger traffic. Finally it closed in 1964 after 300 years of use, and a part was preserved through the work of volunteers.
A three mile section, restored during the 1970s now runs between Sunniside and East Tanfield via Marley Hill and Causey Arch. The present railway has about 40 locomotives in various states of working order as well as victorian carriage rolling stock and a works at Marley Hill. The latter, built in 1854, is the oldest working engine shed in the country. Below I'll try to give some illustrations of present railway and the terrain through which it travelled. This little map should show you where everything is located.

The gentle ride to Tanfield East from Sunniside give some quite scenic views of the Durham countryside, though it has to be said that this has mellowed a lot over the years as coal mining has gradually ceased. When operating at its peak, these views would have been very different as pit winding gear and spoil tips would have been all too evident.

The latter picture location (right), at the Causey Arch halt, is noteworthy. Originally, a more complex junction led away to the west across the Arch itself, through this gap in the trees for the pedestrian footpath.

The Arch was constructed in 1725 and was needed to convey the waggonway across the Causey Burn which flows in a narrow valley with steep sides. To that date, nobody had constructed a single span bridge of this size (45 metres). It was built by a local stone mason, Robert Wood, who had never undertaken anything of this nature ! He used methods employed by the Romans, and it surely must have raised many doubts at the time as to whether the arch would stand. Stand it did, and at the height of coal mining in the area, as many as 1000 coal wagons passed over it every hour. Following a serious explosion at the Tanfield Colliery in 1740, at which many lives were lost, mining declined in the area and the arch gradually fell into neglect; by around 1800, it was used very little, and eventually become quite unsafe. It was restored and stabilised during the 1970s and now comprises part of a country walk from Causey Arch halt passing over and along the Causey Burn.
Beside the Arch, one can see a replica of the wooden coal wagons (chauldrons) used to transport the coal. The lever mechanism at one side was used to tilt the wagon causing it to discharge its contents at the staithes. The wooden wheels and rails caused many problems, notably rapid wear and severe friction, particularly when wet, causing great difficulties for the horse drawn wagons, but also catching fire on occasion too, particularly on inclines. Metal rails supplanted the wooden ones during the 1840s. Imagine one of these wagons traversing the Arch every four seconds !
At Marley Hill stands the engine shed and workshop. This is the oldest working shed in the country and contains much equipment required to service and restore locomotives and rolling stock. I hope to add some more pictures of this on a future visit - on this occasion there was insufficient light due to the overcast conditions.
The Tanfield Railway is very much 'work in progress' - there is much restoration work to be done, a new shed for rolling stock is sought and funds to replace the diesel generators which power the system with a mains connection is subject to public appeal. It's all kept alive by the hard work of volunteers, as with all similar projects. I hope these pictures have brought it a little closer to those who haven't yet managed to pay a visit.