Pencader Tunnel at The Black Mountains

Background

Pencader is a tunnel quite a way from our usual stomping ground of the South Wales valleys, as it is away to the west, close to Carmarthen. However, as it was reported to have some interesting features, we decided it was worth a spending a day visiting it. Construction of this 988yard tunnel was started by the Carmarthen and Cardigan Railway in 1857 with the sinking of the 2 airshafts, and continued until 1861 when the bore was complete. The tunnel was originally intended for a broad-gauge line, and despite the C&C Railway wanting to swap to standard-gauge midway through construction, pressure from a neighbouring broad-gauge company, South Wales Railway, ensured the application for the switch never went to the government.

Work was contracted out to the construction company “Jays of London” by the Carmarthen and Cardigan Railway. At one point there were six workfaces in the tunnel, one from each portal and 2 either way from the bottom of each shaft. The tunnel was still bare rock at this point, and extensive work was still required to complete the rest of the approach cuttings, and also the line southwards to Llanpumsaint. Jays of London had abandoned construction by this time, and work was being carried out by a new company, “Holdens”. By the end of 1863, track had been laid throughout the tunnel.

The line was officially opened on 1st April 1864, but it was still some years before brick lining was installed and up until this point a watchmen had to be employed to check for rockfalls. Construction of the line and tunnel bankrupted the Carmarthen and Cardigan railway, and the company was sold to Great Western in 1881.

Visiting

From a convenient parking spot at the head of Skanda Vale, a forestry track winds down to the valley floor, past some quarry works, right to the track bed. On the way down you can see the pepper pot from the southern airshaft perched on the hill opposite. From the bottom it’s an easy walk back up the ‘bed, past a small workman’s hut made from corrugated iron, to the southern portal. Typically, it was gated, but less typically the were no wobbly bars, loose nuts, convenient gaps through which to squeeze… Just an abundance of anti-climb paint. Oh, and a tiny gap under the fence that was being lashed by a waterfall. A very cold, wet, muddy and grim way in; but the only one available.

We had driven for an hour and a half to get there, and didn’t want to admit defeat. But was it really worth getting soaked, muddy, and chilled to the bone (most likely) squirming through that little hole? Apparently it was, as after much deliberation I found myself on my back in the wet, stripped to the waist, desperately trying to keep as much of my body out the pool as I could by clinging on to the gate above whilst icy water cascaded down around me. Becky had already plucked up the courage to go through, so I guess at that point I had no choice but to chuck the gear over the fence to here and follow.

Having dried off as best we could with toilet roll, I got dressed, emptied (most) of the water out of my wellies, and we geared-up and went inside. Immediately we sank about a foot into the mud. This tunnel was rapidly becoming a test in determination.

Condition today

Getting in is the worst part by far. The waterfall has come about because the tiny viaduct that carries it over the portal is backing up due to a landslide a few yards down stream. Nant Aeron has now cut another path back from the portal, and the pooling water has made the first few yards of the tunnel very damp. Following a dry island directly inside the portal, the level of the floor dips down and very deep mud persists for about 20 yards. I thought I might loose a welly or two. There are a few planks and metal bars around which can be stood on to ease the crossing. Once beyond the mud, the tunnel is dry, as it is at the highest point on the line, connecting the Dolgran valley and Skanda Vale, and water drain away naturally in either direction.

Despite the palaver of finding a way in, this tunnel is really neat and in excellent condition. It is brick-lined throughout, with frequent recesses. The southern airshaft had large amounts of water pouring down it, and at some iron bracing and wooden paneling was visible in the chamber above. Small arches were cut back into the wall below the airshaft, perhaps drainage features. The northern airshaft had very little water coming down it, and no ‘drainage’ archways. Both display an odd construction; the apertures into the tunnel roof are small and brick-lined, but above this, for perhaps 50ft, the shafts are very wide (perhaps the width of the tunnel itself) and unlined. Various reinforcement features can be seen, positioned almost randomly. Above this, the shafts are narrow again and made from brick, more like a well. I don’t know why this arrangement exists, a diagram of it is included below, next to the map.

Despite looking for the entire length of the tunnel we could find no evidence of any side passage whatsoever. The northern portal is also very muddy and wet, and well and truly inaccessible. Guess we’re going out the same we we came in; not something to look forward to. A visit to this tunnel would be best done after a long dry-spell, wellies are essential, and if you have a wetsuit, that would help too.