Mysterious rail tracks leading out to sea were revealed off the Gwynedd coast this week.
For many decades the narrow-gauge tracks had lain submerged beneath waves on the northern end of Barmouth beach.
It is thought shifting sand patterns caused the sea to give up the long-lost railway.
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Most residents in the seaside town had been unaware of their existence.
Among the first to see them was local roofer Dicky Sharp, who quipped he had found the “railway to Cantre’r Gwaelod” – the legendary ancient sunken kingdom of Cardigan Bay.
Others joked the tracks may have once been used to smuggle contraband into Gwynedd.
Their existence came as a surprise to most. “I thought I knew every inch of Barmouth but I have never come across this,” said one person.
When Dicky shared his photos on Facebook, they prompted a succession of theories as to the railway’s purpose.
One person suggested they are remnants of Barmouth’s fishing industry, and were used to bring ships ashore for repairs.
Initial speculation centered on the construction of the town’s sea wall following the great storm of 1928 which devastated sections of the promenade.
In 1930 a series of iron tracks were laid along the prom so that sand and debris could be removed by cart.
More were installed on the beach to carry ballast as steam-powered machinery laboured to construct the wave-return wall.
Half-submerged iron wheels still visible on the beach are believed to have come from one of the vehicles used at the time.
Following this week’s discovery, it was suggested the rail tracks may have been discarded after the 1930 works.
The sea wall theory was rejected by prominent local historian Hugh Griffth Roberts, a retired Snowdonia National Park officer who has assembled what has been called “probably the best collection” of local historic photographs in Britain.
He said: “The sea wall was built by professional contractors and it’s extremely unlikely they would have left valuable equipment lying around in a resort that was building a reputation with its visitors.”
Instead, he said, the railway tracks pre-date the sea wall by at least 40 years and were almost certainly laid in the late 19th Century for the town’s new sewage system.
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Barmouth’s tourist trade was already growing quickly before the arrival of the Cambrian railway line in 1867, the trigger for a major building boom in the town.
A new church was constructed for English-speaking visitors, the town’s Bath House was opened and a small round lock-up, Ty Crwn, began accepting drunken revellers.
The vast majority of new builds were guest houses and hotels. To accommodate the growing population, a reservoir was built at Llyn Bodlyn, above Talybont, in 1873 to provide Barmouth’s public water supply.
All that was missing was an upgraded sewerage system.
“So many guesthouses were being built at the time that means of disposing of the resulting waste become increasingly important,” said Mr Roberts.
“In 1890 a new holding tank and discharge pipe were completed in the area where the rail tracks can now be found.”
Running for around 150 metres, the flap-operated, cast iron pipe discharged raw sewage into the sea at high tide, as was the custom at the time.
In 1987 it was replaced by a new pipe, buried beneath the beach, which discharges treated waste. A sewage plant and pumping station was built the same time.
The narrow gauge tracks used to install the original Victorian system may have been repurposed, believes Mr Roberts.
Since Dicky’s discovery last weekend, a third section of rail track has become visible on the beach at low tide, along with a pair of wheels.
One theory is that they were used to move wheeled bathing machines to the sea’s edge.
Popular until the early 20th Century, these enabled swimmers to wade straight into the sea, thus observing beach etiquette.
Most were propelled in and out of the surf by a horse or horses. However some resorts had wooden rails for the wheels to roll on, and a few even provided steam machines to pull bathing machines in and out by cables.
However the tracks found at Barmouth are narrow gauge, prompting some to question this theory.
Their re-emergence, after so many years, has also underscored ongoing concerns about the area’s coastal processes and the resulting impact on Barmouth’s infrastructure.
The profile of Barmouth beach is under constant threat from high tidal streams and strong currents, with a longshore drift carrying sand northwards.
The West of Wales Shoreline Management Plan notes that Barmouth promenade is was built “too far to seaward at its northern end” and that the town’s groyne system is “ineffective in holding a satisfactory beach against the sea wall” north of the coastguard station.
According to Mr Roberts, cracks have begun appearing “all along the promenade”.
“It’s being undermined by the sand’s disappearance,” he said.
Last March a 10ft hole opened up on the northern promenade following high tides and strong winds. Emergency repairs were carried out after investigations found 180 sq metres of the prom had collapsed.
Inspection of the resulting cavity identified confirmed that 400 sq metres of the sea defence, promenade and adjacent highway had been undermined.
Gwynedd Council was approached for a comment about residents' concerns.