This was originally posted on the #Railnatter Discord and on Mastodon in January 2025

There are two potentially conspicuous problems with the rail network in southeast Wales. (Actually there are many more, but I’m picking on two for this post.)

Firstly, Cardiff Central station is at capacity, both in terms of the number of tracks and trains that can go through it (because of geometric constraints) and because of the passenger capacity of the main station building. Both of these could be fixed by a substantial rebuild, but the main station building, built in the 1930s, is listed, and is considered by many to be the least-altered remaining example of a mainline station of its period, so any significant alterations, let alone demolition, would be politically difficult.

Secondly, on the outskirts of Cardiff there is a museum that specialises in carefully taking apart historic Welsh buildings and rebuilding them brick by brick on their site, which abuts a direct rail line into central Cardiff, but has no rail provision to access the site (and not-great public transport in general: a 30-minute bus every hour).

Fortunately, both of these problems can be solved in a complementary way. All that must be done is to move the current Cardiff Central to St Fagans, where it can be the museum piece that it is. Add passing loops to the two-track line, so that the extra station doesn’t mess up the scheduling of intercity trains on the route, and so that more of the original platforms are used. (It doesn’t recreate a “mainline station” experience if there are only two side platforms.)

To allow for the experience of changing trains at a historic mainline station, and because the rail line is quite a long uphill walk from the main museum building, add a tramway from the station to the main building. The tram stop at the main building could be a replica or a transplant of a heritage railway station, and heritage tram stock could be used (either with modifications for accessibility, or mixed with more modern accessible tram-trains). (I’d suggest having the tramway use the current platform 0; this already has a separate gateline, so if ticket barriers were needed for revenue protection for the rest of the station, the tramway could still be made free without having to install ticket barriers halfway down the underpass.)

Aerial image of the St Fagans site, with the new five-platform St Fagans/former Cardiff Central station to the south, the four mainline tracks and passing loops in orange going southwest-northeast, and the tramway marked in blue heading from the north of the station to the northeast then turning to the northwest to the main building.

This would almost certainly bring more tourism to the museum, and would clear the way for redevelopment of the main Cardiff Central, which is a barrier to new rail services in much of South Wales, without compromising the history of the building.

Issues

This proposal is of course not without problems.

It would be absurdly costly, well beyond the cost of all other building moves to the museum combined. Cardiff Central’s concourse is an underpass beneath the platforms, while the South Wales main line through St Fagans is not far above the level of the River Ely that it runs alongside and crosses there. You would need to raise a significant amount of the surrounding railway to make room for the underpass (although that would also remove a level crossing with one of the main roads through the area). You would also need three new crossings of the River Ely, one for the tramway, one for a pedestrian footway, and one encompassing the eastern station throat and ends of the platforms.

The only way this would make sense would be as part of a huge capital investment into replacing Cardiff Central. With the vast amounts of money that would need to be thrown around for that, a small percentage to relocate the original station and avoid lengthy and expensive delays due to legal challenges from conservationists, might be seen as reasonable. Even so, the cost may end up too high. That said, the move itself doesn’t seem completely unachievable: the main station building is not huge (one reason it suffers with capacity issues) and keeping the original construction for the underpasses and platforms would likely be both impossible and not necessary; for those, rebuilding with modern materials and re-using the original fascias would be sufficient. The platform buildings are very basic.

The only aspect likely to be particularly prohibitive would be the amount of surrounding railway engineering needed (although I’m not a railway engineer so would be happy to be proved wrong on that point!). That said, St Fagans is surprisingly close to sea level given how far inland it is (around 11m above sea level), so it’s possible some of the track may need to be raised at some point for climate resilience, at which point perhaps the numbers could add up?