An extraordinary 21st century analysis of one of Penarth’s major – but unsung – engineering triumphs, the long-forgotten pedestrian tunnel beneath the River Ely, has now revealed just how technically advanced the original Victorian design was.
The pedestrian tunnel ran from what is now Plas Pamir, beneath the River Ely to the area where Cardiff Bay Yacht Club now stands. It was a thoroughfare linking both banks of the river – allowing pedestrians, including hundreds of sailors and dockworkers, to cross the Ely without negotiating the muddy river banks and taking the chain ferry.
The engineering exercise re-appraising the tunnel – or “Subway” as it was called – is part of a remarkable historical website project on Penarth Dock and the Ely Tidal Harbour initiated by engineer (and former Penarthian) David Carder.
In 1966 Mr Carder was an apprentice at the Penarth Dock Engineering Company for which his wife Julie also worked .
His son Martin is now MD of their firm Rota Design Ltd http://www.rota-design.com in Hebden Bridge West Yorkshire and is also involved in the project.
Mr Carder is determined to pull together an authoritative history of Penarth Dock and the Ely Tidal Harbour using original plans, photographs, documents and personal recollections before they are lost in time.
He’s gleaned original detailed drawings showing the “complex geometry” of the tunnel which inclined downward to its midpoint and also curves laterally.
The father and son team have used three-dimensional CAD (computer-aided-design) technology to create a virtual model of the “subway” – as it was called.
Work started on building the original 1250ft-long cast-iron tunnel on July 5th 1897 and – despite two floods during construction – it was completed on May 14th May 1900. Although now sealed off, it’s still in situ beneath the River Ely today .
Victorian pedestrians paid a penny for each crossing. Once inside they found there was 6ft 6 inches of headroom – just enough for a top hat. A string of the newfangled electric light bulbs lit their way as they walked down a steep incline (1 in 7) to a mid-point 50 feet below sea level (at Mean High Water Springs) and then climb the ascent to reach ground-level at the other side.
Any water on the walkway of the tunnel was drained away through grids to pipes beneath and pumped dry. The tunnel also carried gas pipes, water pipes and hydraulic power lines for coal-loading machinery (and later an 11,000 volt electricity cable). The man who designed it was Taff Vale railway engineer George Sibbering .
The tunnel was used until 1936 when Penarth Docks were (temporarily) closed./ It was then re-opened for use as an air-raid shelter during the Second World War and for dock operations when Penarth Docks were taken over by the US Navy in the run-up to D Day. Both entrances were finally bricked up in 1963 .
In 1976 part of the Penarth end of the tunnel was excavated and some cast iron was removed but the rest of it was left in place.
In April 1991 the Cardiff Bay Development Corporation (the body formed to re-develop Cardiff Bay) thought about re-opening the tunnel as a pedestrian link between Penarth and Ferry Road. When consulting engineers Brian Colquhoun & Partners opened up the subway and investigated its condition they found the tunnel was still sound, and water ingress was only “minimal”. It’s still there today hidden and forgotten beneath the bed of River Ely.
It would have cost only £1,000,000 to refurbish the Penarth Subway. The Pont-y-Werin Bridge across the Ely cost £4,500,000 .
David Carter’s remarkable on-line archive on Penarth Docks and the Ely Tidal Harbour is on http://www.penarth-dock.org.uk