Cefn Glas tunnel March 2010

[swanseamale47]

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.

This tunnel is in a poorer state of repair than the other two I did recently, the entrances have had the copeing stones pushed off, and the brick surfaceing has flaked or been broken of in quite a few places. Theres also signs of tunneling for coal in places, this I'm told took place during in the minets strike. Although the tunnel is wet in places with a fair amount of dripping it's dry enough to get into with normal walking boots or even trainers.


The far entrance

Inside the far entrance.

A view along the tunnel

One of the workers safety shelters with graffiti.

Another shelter with graffiti

Courious gap in celing, don't know the use but there were a few along the tunnel

One of the places where a coal seams been mined.

Inside the coal seam it goes appears to go a lot further

One of the places the brick faceing has come off

Some of the junk in the tunnel

A better view of the broken brick faceing

Old wall bracket

Interesting colours in the walls

One of the drainage holes in the floor

Towards the middle of the tunnel

The other entrance

 

[cardiffrail]

Nice one - good to see it is open again. A couple of years back there was palisade fencing at each end.

 

[hnmisty]

Do you think the gap in the ceiling might be to allow for contraction and expansion during different temperatures?

We've got an up-and-down line near us at home, I'll have to put them up some time. The entrances are a lot more overgrown than yours though. And no digging for coal!

 

[swanseamale47]

Do you think the gap in the ceiling might be to allow for contraction and expansion during different temperatures?

We've got an up-and-down line near us at home, I'll have to put them up some time. The entrances are a lot more overgrown than yours though. And no digging for coal!

Well I did think this at one point but then the gaps are funny shaped rather than a simple small gap and I'm not convinced bricks expand or contract much, the tempreture range in the tunnel also probably doesn't vary that greatly either. The other tunnels I have done had nothing like it so I'm slightly at a loss to explain the use. If anybody knows the reason I'd love to hear it.
EDIT. Could it be to allow for subsidance maybe?

Wayne

 

[cardiffrail]

Another tunnel that has similar gaps in brickwork is the Merthyr tunnel. I know that at Merthyr, there were construction issues, with work stopping and restarting, and a change in contractors. I would guess that the same has happened at this location. i.e. its just poor workmanship.