Report - Clydach Twins, South Wales, May 2012

  • Welcome to - 28DL - The UK Urban Exploring / Urban Exploration / Urbex Forums.

    Asylums and Hospitals, High Stuff, Industrial, Leisure Sites, Residential Sites, Military Sites, Mines and Quarries, ROC Posts, Theatres and Cinemas, Draining, Underground Sites, European and International Sites, Leads, Rumours and News, Kit, Clothing, Equipment, Photography and Video sections plus a lot more.

    Please feel free to browse this website as a guest. Creating an account removes some ads, allows you to post replies, start new topics and threads, and gives you access to more features including bookmarking, live chat, messaging and notification systems.

    Create an account | Login | Request new password


28DL Regular User
Regular User
Apr 12, 2011

The tunnels are on the Abergavenny to Brynmawr railway. The original was built upon Baileys Tramway which ran from ironworks at Nantyglo to the Govilon wharf of the Brecon and Abergavenny Canal.

This was converted to a locomotive-hauled railway and in 1862 the line opened from Abergavenny to Brynmawr. In 1877 the line was doubled, and new tunnel bores at Clydach and Gellifelen were made. The new tunnels are the southerly tunnels.

The line was closed in 1958

The eastern portals are on private property and are obscured by trees.

(Bore distances 302 & 330 yards).


A lovely night outside does not always mean a lovely night inside as is the case with the Clydach Twins. As the eastern portals are in somebodies back garden, they have been bricked up so mist is more than present the further east you go. The bores can be accessed from within through an adit near the eastern endss. Visited with wonkycows.

1. Heading down the original bore

2. Dwarf refuge with calcite

3. Access adit to new bore

4. Adit in the new bore

5. Eastern end, new bore, complete with support bracing

6. Brick, soot, mist and rock

7. Gradient marker at the old bore entrance

8. The western portals

Thanks for looking

Similar threads