Morlais Tunnel / Miler Tunnel at The Black Mountains

It was a good day yesterday; not only did we finally get to check out a tunnel that’s been on our to-do list for ages (and it turned out to be the best yet) but we met up with our newest member of the team, Shaun from Pontypridd. Shaun contacted me via the website and asked if he could come along; great, because it’s always good to go in a group, and he knows of a few little-known places to explore around his hometown, so hopefully we’ll have some interesting new urbex visits to do. Anyone else in the area who wants exploration/walking comrades? My email’s in the info section.

Background

I’ve not been able to turn up much about the history of this tunnel; it was opened in 1874 to link the London and North Western railway with the Brecon Mountain Railway, and seems to have been known as the Miler tunnel as well as Morlais tunnel. It closed 90 years later in 1964. It is 900m long, and according to my research it has a maximum depth of 80ft but looking up any of the three airshafts it looks like more than that; however, my OS map puts Pant station at 343m, and the tunnel portals between 310m and 320m, which is about right.

Getting there

This tunnel is within walking distance of Merthyr Tydfil, and is just off the Taff Trail as it runs through Cwm Taf Fechan. Parking is easy; The Brecon Mountain Railway tourist attraction is signposted from the A465 (heads of the valleys road), and there’s a big car park there, although it’s supposed to be for mountain railway visitors. From this car park you can see the pepperpots at the top of the tunnels airshafts. One next to the entrance to the Brecon Mountain Railway, one in the opposite corner of the carpark, and the third in a field in the distance.

Opposite the car park entrance there is a gate leading into a bizarre landscape of spoil heaps and ruined buildings. These buildings are the remnants of an old station, and you can see where the platform used to be. I suspect that this line went on to Morlais quarry, as I don’t see why there’d be one so close to Pant station and the other train lines nearby. If you walk alongside the road going north, eventually you’ll pick up a wide path that curves away to the west. Take this, and straight away the land to your right (the north) starts dropping away quite steeply. The tunnel cutting is just down there; the slope’s not that bad and we went scrabbling down okay, even though it was wet and a bit icy. This is the north portal; the southern one is open, but I think you have to go through private land to get to it.

The tunnel

The first thing that struck me about morlais tunnel is how wide it is; so far all the tunnels I’ve visited have been single track, apart from the westernmost portion of Abernant, but this tunnel was bigger than that! It has a beautifully shaped arch, in excellent condition. Immediately inside the north portal (through a door-sized opening) you’ll find yourself in a lake, but there are stepping stones and a burnt-out car to help you to dry ground, and the water’s not too deep I suppose, and quite clear. With the lake behnid you, the tunnel arcs away gently to the right, straightening up for the last two thirds of it’s length. It is on this straight section that the three airshafts loom above you; I really admire the way these are built. The northern one we found to be emptying water into the tunnel in a torrent, which made for nice photos, but I got pretty wet posing for photos in the deluge. The other two were dry enough. Afterwards I discovered the north airshaft was right next to the toilets at the Mountain Railway building; is that where all the water was coming from? Great.

The tunnel is full of abandoned and burnt out cars. Some are so decomposed they’re little more than rusty patches on the ground. Emerging through these, and other twisted metal debris into the glaring light of the southern portal gave a post-apocalyptic feel to the moment; like something out of a film… Terminator, perhaps. The central pepperpot grate has collapsed in, but has been replaced. Other than that, this tunnel is in excellent nick, and I think it’s very impressive.