(All photos © Sparhawk)

Torpantau - also known as Beacons or Beacon Summit Tunnel - claimed the record for the highest tunnel on the UK's standard gauge network - 1,313 feet above sea level. Reached by a three-mile climb from the south, trains curved sharply right before leaving its darkness on a falling gradient towards Brecon.

The line through it opened for business in 1863 though construction work had finished the previous year. The Brecon and Merthyr Junction Railway (B&MJR) gained the unfortunate nickname of "Breakneck and Murder Railway" due to the number of accidents it suffered which, thanks to its steep gradients, were often severe. Neither was its reputation done any favours by the slowness of its trains. They ground to complete halt when the line shut up shop in 1964.

The structure has a masonry roof but the walls are laregly unlined. Occasional collars of brickwork have been installed for strengthening purposes. Though in generally good condition, the tunnel is now flooded by a stream at its northern end. This water course flows through the bore.

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