Our principal reason for going to Penwyllt, high on the side of the Tawe valley, is to get underground. There is, however, for those who like to know a little more about the places they visit, much to see in the immediate area without having to ask for a key and fill in a route card.
With the help of the book 'The Brecon Forest Tramroads' by Stephen Hughes (see book review), I recently made the most of a lull in the appalling August weather to see what our nineteenth century predecessors had left us in the way of industrial remains. This report describes each of the different features seen on a walk which took about five hours at a reasonably leisurely pace.
Walk south from the SWCC buildings to the obvious ruins of the brickworks. Hughes' book does not have much to say about the remains of the Penwyllt brickworks, these being a much later development than the Brecon Forest Tramroad, which is the subject of the study. However, the site is quite simple and the kilns are easy to identify.
The site was active in the 1890s. The bricks were made by firing a mixture of silica sand and limestone in the right proportions so as to allow the sand to fuse, but without the danger of vitrification, or slagging, whereby the mixture would fuse into a molten glassy mess of calcium silicate. There seem to be two banks of kilns here of different designs. One bank of five round structures is the better preserved. These kilns are at the southern end of the site. They are built of a mixture of fire bricks brought in and of Penwyllt bricks from the kilns themselves.
Note how many different shapes and sizes of bricks were made - there are lots of Penwyllt bricks lying around the site. Many are tapered in one or sometimes two planes. These would have been for use in arches or in round furnace linings. The four kilns in the second bank seem to have a different form with six or so low arches around the outside leading into the centre. The functions of the two types of kiln are probably different.
Close to the second bank of kilns is a brick building with a wide, low arched roof of bricks capped with concrete. Close by are four or five long brick enclosures, possibly boiler houses or fuel stores.
The sand for these brickworks came from pits near Pwll Byfre, which are to be seen later in the walk.
Late Nineteenth Century Limekilns
On the opposite side of the old Neath and Brecon Railway is a bank of four well preserved lime kilns. These date from the second half of the nineteenth century and were served by a siding fron the railway line, the course of which can clearly be seen. The limestone for these kilns came from the crags behind the Swindon Speleological Society cottage which is marked on my 1:25,000 map of the area as a pub! The waste from these kilns was taken across the railway track immediately in front of the kiln drawholes and was piled up on the other side. The waste contains unburnt coal and a white friable concretion caused by the slaking of small particles of lime too small to use. Lime was normally removed as large lumps several inches across. It had to be transported in covered waggons to prevent the rain slaking the lime in a violent exothermic reaction.
The Brecon Forest Tramroad
The Brecon Forest Tramroad was initially built in 1821/2 between Sennybridge and Pwll Byfre, high above Penwyllt. Its purpose was to provide limestone for burning to improve the lands of the Graet Forest, or 'Fforest Fawr', acquired some years earlier from the Government who were selling it off to raise money to fight Napoleon - an early form of privatisation!
Complete ignorance of the geology of the area was one reason why the early plans for the railway were a disaster. It had been hoped that coal would be found high on the moors, supplying the fuel for burning lime. A small trial for coal is supposed to have been made not far from the Pwll Byfre limestone quarry.
To get coal, the line had to be extended to the south. The first scheme for this was a non-starter, the second was partly built from the Drum coal mines up to Penwyllt and halfway up the hill where the intended powered incline was then abandoned, and the third plan was successfully completed using most of the partly built extension but joining the original route some distance south of Crai at a place called Grawen. This was later extended further down the Tawe valley to link up a number of coal mines and iron works and the Swansea Canal. These schemes are outside the scope of this article.
All the tramways were plateways, using three foot long cast iron rails, or tramplates, with an L-shaped section, such as were laid on the Surrey Iron Railway and Croydon Merstham and Godstone Iron Railway between Wandsworth and Merstham in Surrey. The waggons were pulled by trains of horses.
The original line as planned had a falling gradient all the way from Pwll Byfre to Sennybridge thus helping to keep the cartage costs down. The new line had considerable uphill gradients from the coal mines to the limeworks thus making carriage costs high.
The Unfinished Tramway at Penwyllt
Return to SWCC. Notice that in the track outside the row of cottages are a few stone sleeper blocks. Each of these has a round hole into which was once placed an iron spike to hold the tramplates down. These blocks are on the line of the final course of the Brecon Forest Tramroad. The cottages did not exist at the time that the tramroad was in operation. Pass to the rear of the cottages and follow the footpath up the hill towards Top Entrance of Ogof Ffynnon Ddu.
Notice the well made track. This was to be the path trodden by the horses pulling trains of waggons laid between the lines of tramplates. In places, natural subsidence has caused the once level tramway to become uneven.
The path eventually reaches a point where it turns to the right and then rises in a straight line up the hillside. This is the course of the half built incline. It has been cut in half by the later construction of a railway to the silica sand pits at Pwll Byfre. Beyond the more recent railway, the incline continues on a slight embankment, but finally stops short of a bluff of limestone. This is where the line was abandoned in the early 1820s.
At this point, a number of unused stone sleepers are scattered around. From here on, the construction of the incline would have required the excavation of a substantial cutting up to a plateau by Top Entrance, where the engine house would have been sited.
The Silica Sand Railway
Return to the later railway. This was one of two routes taken by waggons carrying sand from Pwll Byfre to the brickworks and limestone from quarries high on the hill. Notice the wooden sleepers on this line which was built using more conventional railway track at a gauge of about 2ft 6ins. By the side of the line you will see old wooden poles that probably once carried signal lines from the base of the incline to the winding house at the top. The old brick and concrete winding house is now a collapsed ruin.
Follow the track on over the moor, passing through a gate. You will pass two limestone quarries which probably used this line for transporting rock down to Penwyllt. After a considerable distance, you will join a forestry track which comes across the valley on your left. Soon after this you will see Pwll Byfre on your right, the sink for the stream that flows through Ogof Ffynnon Ddu.
Just beyond, two cuttings into the hillside on the right are the remains of the sand pits that supplied material to the brickworks. Some old bricks and rails are all that remain of the small buildings and tramway that ran into these workings.
The Original Brecon Forest Tramroad
Walk back to where the forestry track crosses the stream in the valley floor. From this point, the track is following the course of the 1822 tramway from Pwll Byfre to Sennybridge. Turn round and look for some small quarry workings above this point and above the course of the silica sand railway. The course of the Brecon Forest Tramroad diverges from the modern track towards this quarry, crossing over the silica sand railway en route.
Just before the tramway reaches the quarry, a level branch runs off to the left, then sharp left back down to the route you have just walked. Notice a few sleeper blocks in places. Also note how little the quarry was developed in the few years that it was active. The more convenient Penwyllt quarries were used when the line was extended south to the Drum coal mines.
The Silica Sand Railway Zig-Zags
Walk back towards Penwyllt. Look out for an overgrown spur of the railway diverging to the right. If you get back to the gate then you have gone too far. Follow this line. It zig-zags down the hillside and is the course of the other route used for a time from the top of the hill to the brickworks. Narrow gauge locomotives pulled and reversed trains of waggons up this line, using the reversing spurs at the end of each part of the zig-zag.
The line eventually runs down to the Neath and Brecon Railway and ran parallel to it through a cutting. This may have been used as a better route to take limestone from the high quarries down to the limekilns rather than the other line which runs direct to the brickworks down the incline.
The Brecon Forest Tramroad - Later Route
This section of the walk uses a permitted path, closed between 15th April and 10th May, this being lambing season. You can conveniently miss out the next section during this period and jump to the section 'Early Quarrying at Penwyllt'.
The Brecon Forest Tramroad in its final form followed the contours up the valley from Penwyllt, gently rising to Grawen where it met the earlier route coming down from Pwll Byfre. This route was in place by 1825.
When the limestone at Penwyllt began to be exploited, the Pwll Byfre line was abandoned. The Neath and Brecon Railway of 1863 closely followed the route of the Brecon Forest Tramroad, but whereas the latter hugged the hillside closely, the new railway cut directly across the deep ravines that run down the hillside. Thus several cut off loops of the old line can still be traced.
Walking north from the bottom of the zig-zags, you may cross the first ravine on a substantial embankment. On the right, however, the Brecon Forset Tramroad can just about be followed, though the old bridge across the Nant Byfre has more or less disappeared. Better remains can be found further on.
Along the majority of this length of the walk, the old tramroad actually runs to one side of the later railway, although it is not easy to see. Ocassionally the remains of the culverts where drains run off the hillside can be seen.
When you eventually reach another substantial embankment, fight your way off to the right and you will be rewarded by the site of the old tramroad running round on a ledge where the Nant yr Wydd has cut a very large gully into the hillside. A tributary stream also runs down the gully, so there were once two substantial bridges here.
The stonework approaches to the first have fallen away, but the abuttments of the second are still largely in place. The bridges were almost certainly wooden with a timber deck and a trestle arrangement to support it. Notice how railway technology advanced in little over forty years by comparing the sizes of the two sets of earthworks built across this gully.
Early Quarrying at Penwyllt
Walk back to Penwyllt as far as the point where you enter the modern quarry yard. You will have seen the end of the zig-zag railway slowly drop down to the level of the main line. Being of different gauges, the two lines would not have been joined.
Most of the early quarries at Penwyllt have been changed beyond all recognition since the days of the Brecon Forest Tramroad. One still has some early tramway lines around it, but is still substantially larger than when the old tramroad was in operation.
Pass under the old bridge over the old railway and climb up the bank on the right. Follow the track from the bridge across to a small quarry beyond some ruined quarrymen's cottages on the left. A short spur of the tramroad ran round to the left of the quarry to work the limestone bluff from the rear. Another tramroad crossed in front of the quarry, some feet higher than the present floor of the pit, which has been deepened since the tramroad was laid.
The tramway complex around the several quarries and kilns that once existed here has largely been destoyed. A small bank of kilns lie partly ruined to the left of the small quarry you have just visited. They are not easy to inspect, being overgrown. These date back before the days of the later railway.
You have now completed the walk on the route that I followed, and are probably just in time to meet your colleagues who have completed an arduous trip underground, wondering what on earth you could have possibly found to do whilst waiting for them.