Cool it with the tram-trains

Cai ap Gwilym

At a time when scepticism about the benefits of devolution is rife, it is a shame that so few are talking up Trafnidiaeth Cymru (TC).

The South Wales Metro is shaping up to be a genuinely transformative project, with electrification continuing apace, along with station upgrades, frequency improvements, and contactless payment.

Outside of South Wales, trains are increasingly new and clean, featuring the only Wi-Fi network on any rail service in the UK that, in my experience, actually works. Wales’s management of its railways makes a clear case in favour of further devolution, especially considering that the valley lines are the only part of the network that is fully devolved to Wales.

That said, TC is not immune to chasing a misguided fad. Tram-trains have been having something of a moment in transit planning circles, inspired by the success of Germany’s Karlsruhe Stadtbahn.

In short, tram-trains tend to run along conventional railways (known as heavy-rail) in the outskirts, before diverting onto tramways (light-rail) to reach the city centre. This is in contrast to more conventional German ‘S-Bahn’ systems, in which trains stick entirely to the heavy-rail network.

In Karlsruhe, the concept was a roaring success, and owing to some of the similarities between Karlsruhe and the Cardiff metropolitan region, it made sense that TC planners would consider the Karlsruhe model for south Wales. However, there are a number of key differences which suggest we ought to be looking elsewhere for inspiration.

Karlsruhe’s main problem was the 1.8km distance between its main railway station and its CBD. A conventional S-Bahn would not have made sense here, as it would have dropped passengers too far away from their destinations to be of any use.

Karlsruhe’s solution was therefore to use its already-existing tram network, a solution which required very little new infrastructure. Additionally, both the trams and the heavy rail network use low-floor trains, meaning that tram stops in the CBD could remain low-key and unobtrusive, while remaining interoperable with the mainline rail network.

Cardiff Central

By contrast, Cardiff Central is right in the middle of the CBD, thus making the city a perfect candidate for a more conventional S-Bahn-style system. Cardiff also does not have an existing tram network. This means a higher infrastructure cost, for a smaller connectivity gain. And because Welsh railways use high-floor trains, tram stops will also need high platforms, thus making them intrusive, less accessible, and taking up valuable space.

A key asset of the valley lines has also been overlooked. Whereas the heavy railways around Karlsruhe were fully integrated into the rest of the national rail network, the valley lines are almost entirely separate.

There is only one place where the valley lines and the rest of the network share track, which is for a single kilometer through Bridgend station. The infrastructure cost of fully separating the valley lines would be small, especially compared to the potential benefits of separation.

These include increased reliability and service frequency, as well as the potential for some degree of automation in the years ahead, as seen on the excellent Copenhagen S-Tog (The Danish equivalent of S-Bahn).

Tram-trains achieve the opposite. Mixing with road traffic vastly increases the potential for service disruptions, as trams have to contend with traffic signals, pedestrians, cyclists, and bad drivers.

Integrating street-running trams into the heavy rail network means that the whole system now has to make allowance for these potential disruptions, reducing service frequency. It also increases the potential for delays within Cardiff to cascade further up the line, affecting commuters who are not even travelling on the same route.

Downgrade

Tram-trains therefore force a downgrade of the entire system. So why are we doing this? It all comes down to Cardiff Bay. While Cardiff’s CBD doesn’t suffer from a last-mile problem, Cardiff Bay does.

To solve this, we are building a new tram line directly linking the bay to Cardiff Central, before integrating into the valley lines network to allow direct services along a new rail branch up towards Llantrisant.

A tram is a perfectly good solution for linking Central to the bay, but it doesn’t need to be integrated into the valley lines. One-seat rides are overrated; you don’t need them as long as the tram connection is frequent enough.

And as the new branch to Llantrisant is mostly greenfield along a former railway alignment, there is no need for this to be constructed to light-rail standards either. Additionally, a separate tramway could use low-floor platforms, thus facilitating further expansion along space-constrained city streets.

Toilets

So to make this clear: We are limiting the potential of the entire valley lines network, all for the sake of a few hundred meters of street-running in Cardiff Bay. Cardiff Bay is not even the city’s main centre of employment, so why prioritise it over the needs and comfort of commuters travelling from 38 kilometres upriver? Not to mention the lack of toilets…

The South Wales Metro is a truly fantastic project, so it is a shame to see it undermined by the present fad for penny-pinching downgrades.

Amid a sea of bureaucratic mediocrity, railways are one area where Wales is unabashedly aiming high. Let’s not get in our own way by compromising on quality. If devolution is to succeed, it should deliver the very best.

Cai ap Gwilym is a PhD candidate in anthropology at the LSE

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