It’s curious how certain places exert a disproportionate influence on our thoughts. More than 40 years ago I stood on a bridge and took a photo of a railway at Penrhos, near Caerphilly. I have no idea why – not a single train graced the lonely route up the big hill from Nantgarw towards Caerphilly.

Perhaps I sensed the pull of the ghosts of trains past. Penrhos was the site of a mighty battle. Three Welsh railways locked horns on that hillside. The Rhymney was the oldest, opened in 1858 to transport coal from its namesake valley to Cardiff. The later Pontypridd, Caerphilly and Newport hauled the black gold from the Taff and Rhondda valleys to Newport. But the star of the show was the Barry Railway, the parasite that drew trade from the incumbents to its own, new port of Barry. By 1914, Barry had overtaken Cardiff as the world’s greatest coal-exporting port.

At the start of the 20th century, the Barry Railway set off on an outrageous, audacious venture to steal traffic from its earlier rivals. It blew vast sums on a line that soared against the grain of the South Wales landscape. Its new line spanned spectacular viaducts across the Taff and Rhymney valleys to join the Brecon & Merthyr Railway opposite Llanbradach. The expensive line was closed by the Great Western Railway, which absorbed the Welsh railways exactly a century ago, and the great viaducts demolished in 1937, as my father recorded during his reporting career after the second world war. (The steel was recycled for Britain’s frantic rearmament on the eve of Hitler’s war.)

One of the Barry’s more modest bridges crossed the Rhymney and PC&N lines at Penrhos, just west of Caerphilly, seen in Briwnant’s image above. By the time I took my first photos here in the early 1980s just one double track line remained. Within a year even that route had closed.

Yet the pull of that lonely hillside still captured me. In the snows that followed Christmas 1993, Dad and I drove over Caerphilly Mountain to witness Penrhos, now bleak and rail-less. The pillars of the Barry’s overbridge provided the only evidence of a lost railway. I don’t remember mourning this monument to the loss of South Wales’s industrial might. But I feel it keenly now. Forty years ago, no one thought the loss of king coal was a victory for planet Earth. But let us cling to that consolation.

When the rails left Penrhos, the coal trains from the Rhymney valley were restricted to the later 1871 Rhymney Railway mainline through the tunnel to Llanishen and Cardiff. Lying in my bed in Lakeside, Cardiff, as night became Bible black, I took comfort in the throb of the class 37 diesels as they piloted their black gold cargoes down the embankment towards Cardiff. The diesel song occasionally joined in harmony with City Hall’s bells sounding the hour, and the foghorns of the capital’s still active docks.

The reign of king coal is over. The surviving South Wales rail lines are largely devoted to human not industrial traffic. Some of the lines closed by the malevolent Dr Beeching have reopened in the past 35 years, with more to follow. But Penrhos is unlikely to echo once more to the sound of trains. Any dreams of a resurgence will be confined to small scale models. North of the road bridge where Dad and I parked our cars the railway cutting has been filled in as a foundation for Caerphilly’s expansion.

I’ll end with an image of Penrhos in its twilight days. The photo above shows the Barry viaduct intact, but disused, as a GWR coal train steams up the hill from Taffs Well. Today, the hillsides echo to footsteps and barking dogs rather than panting trains. We can but dream of the days when Welsh steam coal fuelled the world.