Torpantau Tunnel, Brecon
Torpantau Tunnel, also known as Brecon Summit Tunnel, was the highest on the UK's standard gauge network. It sat 400 metres above sea level. Trains climbed for four kilometres from the south at gradients of 1:47 and 1:55. They then curved sharply right. Exiting the tunnel, trains ran onto a steep 1:37 decline towards Brecon. The tunnel opened in 1863, with construction ending a year prior. The Brecon & Merthyr Junction Railway (B&MJR) was nicknamed the “Breakneck and Murder Railway”. Many accidents occurred, often severe due to the steep slopes. The slow speed of the trains didn't help its reputation. The tunnel section closed on 4th May 1964, with only freight trains running. Passenger services on the B&MJR ended in January 1963.
Torpantau Tunnel is 610 metres long. Its masonry arch rests on shelves cut into the rock. Brick or stone sidewalls were added over time as needed. Refuges are built into the tunnel walls. The south portal is masonry. It's wedged into a cutting with vertical sides. A wing wall retains the west face for a short distance. The north portal (facing ESE) is a larger stone structure. It projects into a cutting with more gently sloping sides.
The tunnel is in decent shape overall. However, small rockfalls have happened, with debris on the floor. A stream runs through the tunnel. Both approach cuttings are waterlogged. The narrow-gauge Brecon Mountain Railway uses the trackbed south of Torpantau since 1980. They hope to extend operations north through the tunnel in the future.
