# Gwfylchi tunnel (aka Tonmawr) July 2010



## swanseamale47 (Jul 8, 2010)

The Gyfylchi tunnel is 1124 yeards long. It was the only tunnel on the South Wales Mineral Railway, a mere 12mile stretch of track that ran down from Glyncorrwg, via Tonmawr to the docks at Briton Ferry, in Neath. 
It was started in 1853, and it was opened in sections between 1861 and 1863. When opened it was a broad 7′ 1/2″ gauge, but in 1872 the line was adjusted to standard gauge. This allowed junctions with the Great Western Railway. 
The line was built for the mines and quarries around Glyncorrwg and the mines in the Pelenna valley, taking the minerals (for example, limestone, dolomite, coal) to the docks at Briton Ferry. Although there was never a passenger service on the line, people from the isolated Glyncorrwg valley commonly were allowed to ride in the empty wagon or in the brake carts for free, to visit Neath in order to trade. 
The line was single track apart from 2 passing places, one at Cymmer and one at Tonmawr; it was standard practice fro trains to pass at Cymmer unless special instructions had been given. On August 16th 1902 the train leaving Glyncorrwg intended to pass at Tonmawr, but without the proper authorisation. Due to this, the train leaving Briton Ferry was expecting to pass at Cymmer as normal and the two trains collided head on inside the tunnel, both drivers suffering injuries and many of the villagers who were riding in the wagons were injured, 2 of them fatally. 
In 1910 the section of track between Tonmawr and Briton ferry was dismantled, and all traffic went now to Port Talbot. In 1925 the Glyncorrwg colliery closed, although the line still served quarries in other parts of the valley. In 1947 the Tonmawr end of the tunnel collapsed and it was never reopened.


The tunnel today is flooded for a fair part of it's length, the entrance is dry but get's wetter as you go further, one report suggests it's flooded to a depth of around 12 foot at the far end of the tunnel, I probably got a few hundred yards before coming to the water (see pics) A word of caution the roof has several small patches of brick that has come off and fallen, not much but care is advised just in case.


The entrance outside






The entrace inside





Looking back towards the entrance




One of the safety niches for the workmen





unknowen object, maybe a marker post? but looks too new





Some of the fallen brickwork





Part of the brickwork





A view along the tunnel





another shoot showing the ridges from the sleepers





Some of the rock wall





The start of the flooded section





Another view of the flooded section, this was as far as I was prepared to go


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