Rhondda Tunnel

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v t e Rhondda and Swansea Bay Railway
Legend
Taff Vale Railway to Pontypridd Treherbert Treherbert Junction Blaenrhondda Taff Vale Railway to Rhondda Fawr Collieries Rhondda Tunnel 3443 yd 3148 m Blaengwynfi Gelli Tunnel 174 yd 159 m Croeserw Viaduct Llynvi and Ogmore Railway to Abergwynfi Sth Wales Mineral Rly to Glyncorrwg Cymmer Afan Llynvi and Ogmore Railway to Maesteg Sth Wales Mineral Rly to Tonmawr Duffryn Rhondda Halt Cynonville Halt Pontrhydyfen Port Talbot Railway to Tonmawr Port Talbot Railway to Bryn Cwmavon Glam Aberavon Town East Junction South Wales Railway to Swansea South Wales Railway to Cardiff Port Talbot Railway to Port Talbot Old Dock Port Talbot New Dock Aberavon (Seaside) South Wales Railway to Port Talbot Baglan Sands Halt Briton Ferry Dock Briton Ferry East Briton Ferry Sth Wales Mineral Rly to Tonmawr Court Sart Court Sart Junction South Wales Railway to Neath Neath Canal Side Neath Harbour Junction Swing Bridge over River Neath Vale of Neath Railway to Neath Abbey Swansea District Line to Llandarcy Jersey Marine South Jn Cardonnel Junction Cape Platform Great Western Railway to Briton Ferry Road Jersey Marine Baldwins Halt Danygraig Halt Great Western Railway to Swansea East Dock Swansea East Docks Swansea Riverside Swansea Harbour Trust

The Rhondda Tunnel is an abandoned railway tunnel that runs between the Rhondda and the Afan Valleys in South Wales. It is 3,443 yards (3,148 m) long, making it the third longest railway tunnel in Wales, and the seventeenth longest in the United Kingdom.^[1]

The tunnel, constructed by the Rhondda and Swansea Bay Railway, was engineered by Sydney William Yockney. In June 1885, construction commenced from Blaencwm in the Rhondda Valley and Blaengwynfi in the Afan Valley. Progress slowed because of manpower shortages and water seepage. Progress was restored when the original contractor, William Jones, was replaced by Lucas and Aird, who brought in more men. Completed on 2 July 1890, the tunnel has a single 58-foot (18 m) ventilation shaft around 105 yards (96 m) from its western end. It is almost 1,000 feet (300 m) feet below the surface at its deepest point. The tunnel's single track line split into double track on either side of its portals.

Within decades of opening, the tunnel lining became distorted because of mining activity in the close vicinity. Between 1938 and 1953, around 500 steel ribs were installed to address the issue but it continued to deteriorate and speed limits were imposed. In 1969, the tunnel was closed temporarily on safety grounds. In December 1970, the Ministry of Transport closed the tunnel permanently, rather than financing repairs. In 1980, both entrances were filled. During the 2010s, the tunnel was surveyed with the intention of reopening it as a cycleway.