CN417

Penrhyn Quarry Railway  

13/09/2021  

Designated  

Gwynedd  

Llandygai  

261000  

368367  

Water Supply and Drainage  

Railway  

Industrial  

The monument comprises the relict remains of the Penrhyn Slate Quarry Railway, developed during the 1870s to replace the Penrhyn Quarry Railroad (CN415). The railway utilised a similar route to the 1801 railroad between Felin Fawr Slate-Slab Mills and Dinas Incline, in part, using the same formation. However, at Tregarth, the route diverted west along the Cegin Valley to Porth Penrhyn, Bangor. Powered by steam locomotive from the outset the railway used a 2’ gauge rail. It was built to a similar design as the Ffestiniog Railway although it was unusually steep - a maximum gradient of 1/33 was used in order to avoid the need for inclined planes as used by its predecessor. It followed a more circuitous route than the railroad, being almost 10km in length, with passing-loops at Felin Hen and Tregarth. The Penrhyn Quarry Railway was designed by Charles Easton Spooner of the Ffestiniog Railway for the sole use of Penrhyn Slate Quarry (CN416), although a passenger service was also operated for the quarrymen from 1880 to 1947. It remained in operation until 1962, and was dismantled three years later. The railway today survives as four relict sections: Area A – Felin Fawr to Hendurnpike, Area B – Hendurnpike to Tregarth, Area C – Moel Y Ci to Rhydau Duon, and Area D – Pont Felin Hen to Coed Hywel Uchaf. Area A: Felin Fawr to Hendurnpike. At the N end of the Felin Fawr Slate-Slab Mills the railway formation sits within a cutting beneath a footbridge. From here, the 1870s railway originally followed the line of the earlier Railroad (CN415) but by the 1890s a new section was completed to the E. The first 150m of this route survives as a slate formation on a pre-existing slate waste tip until it reaches St Anne’s Hill. This section has been partly restored in recent years. The timber bridge and abutments of St Anne’s Bridge were cleared in the 1980s but the formation north of the road survives, partly buried by slate waste and in overgrown woodland. At the summit of the Ty’n Y Clwt inclined plane the railway bisects the earlier railroad and continues along a well-preserved slate causeway c.5m high, crossing the Pen y Ffriddoedd footpath on a bridge made of rolled iron joists. The railway continues north, first as a cutting flanked by crawiau (traditional slate and wire fences) then as a substantial embankment c.4m high on the E elevation. The formation continues to Nant y Graean Isa where its route becomes fossilised up to Hendurnpike level crossing where a small ‘crossing-keeper’s cabin’ remains in use as a domestic outbuilding. Whilst much of the track was salvaged after the railway was decommissioned, some sleepers remain in situ and fragments of rail and other ferrous artefacts have been discovered along and adjacent to the railway in Area A. Area B: Hen Durnpike to Tregarth. The southern extent of Area B follows the route of the Penrhyn Quarry Railroad for the first c700m until it reaches the summit of the Dinas Incline. The first 350m from Hendurnpike flanks the W side of the turnpike road. It is rock cut on the upslope and supported on a massive rubble-built embankment on the downslope side, c.4m above the modern road. The next 350m follows the contour but also retains a substantial slate-slab retaining wall. Visible stratigraphy is evident along this length, presumed to be evidence of the transition during the 1870s from horse haulage to steam, and from railroad to railway. Some evidence of the Dinas Incline winder house survives but this area was mostly cleared by 1879. The Penrhyn Quarry Railway, then turns sharply on a slate-rubble embankment and continues west for c. 300m flanked on both sides by crawiau. It reaches the road from Hendurnpike to Tregath where the slate-rubble abutments and wingwalls of the Corrig Llwydion railway bridge survive. Thereafter the railway is carried over the Bethesda branch of the London & North Western Railway on a brick-built, single-arch skew bridge and then continues; first as a terrace cut into the bedrock, then as a substantial earthwork for a further 550m west to the location of Tregarth Station. Here an in-filled, stone-built arched bridge carries the main street of Tregarth over the course of the railway. Area C: Moel Y Ci to Pont Felin Hen. To the W of Tregarth the railway followed the natural topography. While the route is fossilised there are no extant physical remains apparent until the Moel y Ci allotments where an engineered cutting is visible, in use as a public footpath. Here the formation retains a bank surmounted by slate crawiau along the southern flank and a wrought iron post and rail fence defines the north of the area. Occasional in situ sleepers survive along this section. The cutting extends for c.250m then emerges as a low earthwork before being buried around the Moel y Ci Nurseries. The Ordnance Survey 1st Edition map (1889) illustrates a farm track to Moel y Ci farm which crossed the railway. The single-arch-stone overbridge survives here although is no longer in use. Thereafter for around 200m west the formation survives as a mostly buried feature and is just visible through scrub and trees as a cutting before turning north towards Rhydau Duon. The cutting at Rhydau Duon survives for c.150m in woodland and is exceptionally well preserved with in situ sleepers and sections of rail evident. The substantial cutting is up to 25m in width and in some places more than 5m deep illustrating the archaeological potential of the buried sections further east. Beyond the cutting, the formation makes use of a large earth causeway some 7m wide and that today supports the driveway to Rhydau Duon. The causeway incorporates a large culvert at its base that carries a nearby watercourse beneath the route of the railway. An area of significant archaeological potential survives at Pont Felin Hen. While the bridge itself has been removed the southern abutments and wing walls remain in situ. The ruinous remains of the Felin Hen waiting shelter survive alongside a set of slate steps that provided a foot crossing. A large milepost is recorded as having been located in this area during the 1940s and may survive in the surrounding woodland. Area D: Pont Felin Hen to Coed Hywel Uchaf. To the north of the Pentir Road the formation descended via a steep gradient and today survives as a well-preserved cutting. The cutting includes some stone revetments and is partly flanked by crawiau for c.600m through dense woodland. The route of the London & North Western Railway is carried by a bridge across the railway formation and the cutting survives for a further c.100m through agricultural land to the northeast before being infilled. The monument is of national importance for its potential to enhance our understanding of the slate quarrying industry, specifically the evolution of transport systems and the development of international export. The railway includes several substantial structures including slate- and earth-built causeways and embankments. The monument also incorporates much of the earlier 1801 Penrhyn Quarry Railroad (CN415) formation and as such retains significant archaeological potential. The scheduled area comprises the remains described and an area around them within which related evidence may be expected to survive. The scheduled area is divided into 4 linear polygons that encompass the line of the railway and associated structures: Area A varies between 5 and 10m in width and is c.1200m in length orientated NNW-SSE between NGR 261460, 366460 – 261025, 367540. The first part of Area B is between 5 and 12m in width and 700m in length orientated N-S. The second part of Area B is between 5 and 20m in width and c.850m in length orientated E-W. Area B is located between NGR 261010, 367720 – 260260, 367950. Area C comprises a linear section c.25m in width and c.1km in length orientated E-W and then N-S between NGR 259680, 367885 – 258840, 368000. Area C also includes an irregular polygon c.60m N-S by c.25m transversely centred on NGR 258880, 368190. Area D is c.10m in width and 600m in length orientated N-S between NGR 259000, 368390 – 258915, 368975.