The Nantlle Railway (or Nantlle Tramway) was a Welsh narrow gauge railway. It was built to carry slate from several slate quarries across the Nantlle Valley to the harbour at Caernarfon for export by sea. The line provided a passenger service between Caernarfon and Talysarn from 1856 to 1865. It was the first public railway to be operated in North Wales.
A tramway linking the Nantlle slate quarries to Caernarfon was proposed in the 1810s. The Nantlle Railway was authorised by an Act of Parliament in May 1825, and the company began construction of the railway. The line was designed and constructed by George Stephenson and his son, Robert. The line opened in 1828 and was operated using horses. [George Stephenson and his BROTHER Robert, not his son Robert; viz. letters from Robert snr. to his brother in Liverpool quoted by Boyd (N.Caerns Vol.I p.15>). These letters in the Phillimore collection and the Institution of Mechanical Engineers.]
During the 1860s and 1870s, a portion of the line was replaced by the standard gauge branch of the London and North Western Railway (LNWR) which acquired the line in the late 1860s. The Nantlle Railway was closed in 1963 by British Railways (BR), when it was the last line to be operated by BR using horse traction. Much of the route has been overlaid with roads or obliterated by other developments, but several railway structures remain. Two miles of the northern section of the original Nantlle Railway trackbed, between and the Coed Helen Lane tunnel, are part of the reopened Welsh Highland Railway, although much is off line as was the Carnarvonshire Railway route on which the restored WHR was constructed.
History
Background
The first proposals for a railway in the Nantlle Valley were made during 1813. Slate quarries had developed to north and west of Nantlle, and the slate was transported to wharves at Caernarfon by pack horse. A more efficient system was required to enable the quarries to compete with Dinorwic and Penrhyn.
A route for the line was surveyed, running westwards from tramways linked to the quarries, towards Talysarn and Penygroes. The line then turned northwards, passing through Groeslon, Llanwnda, Dinas and Bontnewydd. The line was also carried copper from the mine at Drws-y-coed, to the east of Nantlle.
The Act of Parliament for the Nantlle Railway was passed on 20 May 1825. The Nantlle Railway Company was incorporated in June 1825 to construct and operate the railway, and in August 1825 it advertised for a sub-contractor to build the line. The company raised a working capital of £20,000 by issuing shares at £100 each. Most of the shareholders were owners of the quarries served by the line. The chief engineer was the railway pioneer George Stephenson, and construction was overseen by his son Robert, who was assisted by John Gillespie.
The line was run as a toll road with customers charged a fee for their goods to be hauled to their destination.
Construction
On 21 March 1827, a second Act was passed, authorising an additional £70,000 of shares to finance construction. The act mortgaged the railway's infrastructure, and restricted the fees it could charge until all debts were paid. On 23 May 1828, in response to slower than expected progress, a third Act was passed extending by five years the time available for construction. Robert Williams of Bangor was appointed the resident engineer and William Owen of Gwaenfynydd, Anglesey was contracted to construct the railway.
The railway required significant civil engineering work, including a long embankment and culvert to the west of Bontnewydd, two tunnels, and a bridge. The short Coed Helen Tunnel carried the line underneath a road on a gentle gradient, rising from north to south. Its walls and roof were built of coursed blocks up to long. The line crossed under the driveway of Plas Dinas house in the long Plas Dinas Tunnel. It was wide and had a semi-circular arched roof, high, made of three rings of brick, supported on walls of stone rubble. The Plas Dinas Tunnel is approached by a pair of deep cuttings.
The Afon Gwyrfai Bridge is long with a single arch that carried the railway over the Afon Gwyrfai to the west of Bontnewydd. It is wide at its base, narrowing towards the crown and above water level. It is built from rusticated stone blocks. In September 1999, the Afon Gwyrfai Bridge was listed as a Grade II structure.
The track was laid with lightweight wrought iron fish-bellied rails to , significantly wider than the gauge found on contemporary quarry railways, and narrower than the which became the standard gauge.