Cefn Glas Tunnel / Quakers Yard Tunnel at The Black Mountains

History

I was excited to discover another abandoned tunnel on one of my maps recently, that was near to home. The Cefn Glas tunnel was dug in 1851 to allow trains on the Pontypool to neath GWR extension line through Craig-yr-Efail, the mountain with the bite out of the top that lays between Treharris and Aberdare. It is named after Cefn Glas colliery, the site of which was just north-west of the east portal of the tunnel. A canal ran around the curve of Craig-yr-efail, also just above this portal. To the east, the trainline crossed over one of three closely-grouped viaducts over the river Taf, and on to Quakers Yard. To the west, trains ran through to Aberdare. It would seem that the tunnel often suffered drainage problems during its lifetime, until closure in 1964. The tunnel is 704yards long, and single track all the way. Many thanks to the Cardiff Rail website for a lot of this info; check this web page out also for images of the eastern portal, which I don’t yet have.

Getting there

We went in from the western portal of this tunnel, on the A4059 Abercynon road. From what I can tell, access to the east portal is best undertaken from the picnic spot on the A470 that is about 1 mile north of the east portal. From here, the route of the old canal should take you all the way to the tunnel. It does appear, however, that you can get there from Edwardsville via a path that take you over the Taf on a bridge and under the A470 and new train lines via tunnels. On the A4059, after leaving the large roundabout, there are two left hand turns close together. The first goes to Abercynon. The second curves back round to the Phillips factory, and has a small parking spot on it that we used. A short-cut takes you over a fence and a ditch and back onto the main road. There are two ways to go from here; you can either go right until you reach another parking spot by some disused gates, cross the road and scrabble up the bank as we did. At the top, when you reach the path, you have to double back on yourself to reach the tunnel cutting. An easier way is to find the wide path opposite the factory turning. This takes you through an old underpass; this is under the dismantled railway, and will make the tunnel very easy to find. The walk would take about 10 minutes total. Investigate the ruined building foundations near this underpass – could it have been an old signal box?

The Tunnel

Outside the west portal several large chunks of masonry have been pushed out the tunnel entrance by tree roots. As usual, the fence has a HUGE gap in it, and you can walk right in. The first few meters of the tunnel curve to the left, and after no time at all you’ll find that the other end is visible. The tunnel is pretty dry inside, with lots of junk at the start that people have craftily tipped there (seems a bit of an effort. Surely it’s easier to go to the dump?). The roof and sides of the tunnel are a patchwork of repairs and mineral deposits. There is graffiti in some of the recesses warning you of your impending doom. The main thing to note here is that as you go further east, the collapsed sections of wall and roof lining get larger and more concerning, so much so that we turned back after about 2/3 of the length. THESE COLLAPSED SECTIONS INDICATE THE TUNNEL IS NOT COMPLETELY SAFE, EXERCISE CAUTION! I’d actually be tempted to bring a hard hat for this if you do intend to visit, and as always, don’t go alone.

Map

Map of the west portal

Photos

Getting equipped
Western portal
Hanging roots
Light from the east
Getting rough
Time to go…
Point taken
Back into the light
Ruined building
Underpass

Part 2 – Visiting the Eastern portal

space

Part 2 – Visiting the Eastern portal

The Walk

I parked on the picnic spot on the A470 going north. From the picnic area, I scrambled up the icy slope and over a fence, and found myself on a small tarmac road, which was part of the Taff Trail. So I set off south, with the forest to my right. After a while, I passed some really out-of-the-way houses, and then reached a junction. The Taff Trail went left, under the A470. To the right, the road carried on up the hill, so I went this way at first but then decided it was wrong, and came back. At least I got a nice photo of the misty valley when I was up there. The right way to go was straight on, along a wide winding path that had a deep drain next to it. Eventually this lead to a gate, with an old bridge to the side, from when this path was on the embankment of a canal. I then followed the dry canal through some ruined buildings, which I think are the remnants of Cefn Glas mine. After a short distance the cutting for the tunnel was on my left, directly under a pylon that hissed and popped in the damp air. Viewed from atop the tunnel portal, the cutting is a perfect long U-shape, and reminded me of the Circus Maximus in Rome. The path down to the portal was very slippery, wet leaves on frozen ground, and I was glad of my walking boots. Directly in front of the portal, the ground was a complete bog, soggy mud about a foot deep. I found a dry way in by using the collapsed facade as steeping stones, and a fallen tree as a little bridge (one I’d scraped the ice off). The tunnel is deteriorating. Compare my photo of the portal now, with this one posted on flickr exactly a year ago. Much of the facade has collapsed. I took a few quick snaps in the tunnel, and I didn’t venture very far in.

Pontygwaith Bridge

On my return journey I detoured under the main road, and took a photo of Pontygwaith Bridge. This is a very pretty old bridge, and because of its high arch, the roadbed going over it is the steepest I have ever known. A plaque nearby says “Pont-y-gwaith, meaning the ‘works bridge’ was constructed in 1811 to replace a wooden bridge associated with the nearby 16th century ironworks”. So it’s coming up for its 200th birthday then; cool.