The Stainmore Route Viaducts

For anyone old enough to have travelled on the Stainmore Line the most enduring memories even after half a century must be of those dizzying views as the train rumbled across the high iron of the three big viaducts along the line. Each had it's own distinctive sound and special quality. From Belah in spring and autumn there were awesome views of sunsets down the Eden Valley from the the teatime train from Darlington as it steamed through windy space so far above the darkening moorland below. The dense wooded ravine of mysterious Deepdale could be come and gone in a flash as regulators were pushed full open and you skimmed along seemingly miles above the tree tops as the locomotive accelerated away from Lartington and got into its stride for the steep climb up to Bowes. And my personal favourite - Tees Valley - where suddenly pastoral views of grazing cows made way for the forested canyon of the wild peat-stained river below and you could see far down beyond Barnard Castle and to the blue line of moorlands of the 'Stang' beyond the Greta valley to the south.

As a child I was lucky enough to walk across all three of these viaducts with my granddad Wilf Ransom as I went with him on his shift as a signalman. Belah and Deepdale had solid timber decking which made them liable to catch fire and a careful watch had to be kept in dry weather, but at least the deck was solid. Tees Valley was the scariest, it only had thin iron plate decking with drainage holes and you could see the river churning far below your toes and just a quarter inch of metal. Once half way over in the dark we met a westbound mineral coming out of Barnard Castle. The leading 4MT had a banker and as the train accelerated past us racing at the hill ahead the whole structure shook like a leaf. I can still remember the din from those steel coal hoppers, the sparks leaping from loose brake blocks and the glow of the locomotive fireboxes as they roared past just a few feet away.

The SD&LUR Board had limited capital and Thomas Bouch needed to engineer the route frugally. This was achieved by keeping earthworks to a minimum but at the cost of a gradient profile that was exceptionally severe for its day, with grueling stretches of 1 in 60 (17‰ grade) or worse on either side of Stainmore Summit. The line generally followed the contours of the land but there were several places where it was just not possible to avoid crossing valleys. In the end twelve viaducts needed to be built of which two were entirely iron structures, two employed masonry piers and iron girders and eight were masonry arches.

The eastern section of the line from Spring Gardens Junction near West Auckland climbed on the north side of the Gaunless River and then crossed it towards Cockfield station on the masonry and iron Lands Viaduct. The remainder of the route to Barnard Castle included two stone viaducts across small and remote valleys at Langleydale and Forthburn. They are far from public roads and few pictures seem to have survived of any of these structures in use although the bridges themselves are still there.

Leaving Barnard Castle for the west Percy Beck Viaduct was a stone structure across a wooded ravine right at the exit from the station yard. It still survives as a private access road. Half a mile further on was the masonry and iron Tees Viaduct built by Thomas William Kennard, the Welsh contractor who was responsible for the Crumlin Viaduct in Monmouthshire. Then the line swung southwards past Lartington to cross Deepdale on a big iron trestle viaduct identical in construction to the larger viaduct further west at Belah. Bouch had no experience of this kind of iron construction, and for the calculations required for specifications he relied on the civil engineer and mathematician Robert Henry Bow, an expert in braced iron structures. Part of the design work and the logistics of construction were also handled by the contractors, Gilkes Wilson of Middlesbrough, a company that worked in close partnership with the Stockton and Darlington Railway for years and was responsible for building many of their locomotives. The components were prefabricated off-site. Deepdale was erected by a team of 60 of their workmen in just 80 days. It isn't often appreciated that, although built to 24' width, both structures initially only carried one track down the centre.

Between the two big trestle viaducts on either side of the summit were 13 miles of track with only one small stone viaduct at Mousegill, just north of Barras station. Sadly in 1966 this was blown up by the army, but thanks to the local landowner the remote viaduct at Hatygill on the line down from Belah to Rookby Scarth was saved from a similar fate.

The last three viaducts on the route were all stone built and are easily accessible for visitors today. Merrygill Viaduct at Hartley and Podgill Viaduct a short distance further south are both included in the railway walk that follows the route of the railway from Stenkrith Bridge up to Hartley. The stone viaduct at Smardale Gill is the largest and arguably the most beautiful of all the surviving structures along the railway, and can be accessed by walking along the line either southwards from Smardale or northwards from Newbiggin. All three of these structures in the Kirkby Stephen area are now well preserved and protected, the property of the Northern Viaduct Trust. But it is still sad to think that three such unique and historic structures as the Bouch high iron viaducts which formed such an important part of the Victorian engineering legacy have been so recently destroyed for their trivial scrap value.