The UK is on the verge of a radical tram-train revolution

The UK’s first hybrid tram-train has been operating for a year. Now Glasgow, Manchester and areas in Wales are looking to build their own versions.

One piece of track part of the way between Meadowhall South, in Sheffield, and Rotherham Central is unique. As a tram makes the journey, it slides onto the special section of track that connects it to the main rail network. There, it switches from driver controls to rail signalling, acting not like a tram but a train.

This fusion of light and heavy rail infrastructure is the UK’s first tram-train – and if South Yorkshire’s trial continues to be as popular in the second year as the first, we could see more hybrid services across the country.

Trams are ideal for inner-city public transport: they are above ground for easy access, have clear routes that can’t be diverted like a bus, and most are electric powered for no emissions. But they aren’t great for linking together our cities, which are further apart and tend to be connected by higher speed rail networks.

To get the best of both worlds, you have to cram them together into a hybrid known as the tram-train, a vehicle that can run on tram networks as well as standard heavy rail, despite their different power, communications, signalling and safety regulations. “The benefit is that if you already have a good tram network in your city and a relatively unbusy mainline railway network around the city, you can provide direct services from the suburbs to the city centre without building too much infrastructure,” says Taku Fujiyama, a lecturer at University College London’s faculty of engineering science.

The tram-train trundling between Rochester and Sheffield city centre is the first of its kind in the UK, but the idea has long been used elsewhere, originating in the German city of Karlsruhe in 1992. (The UK does have trams that run on former train lines, but in those cases no standard train services operate as well, so they can continue to behave like trams throughout their journey.)

Britain’s first tram-train started operating on October 2018 in South Yorkshire after a six year delay and quadrupling of costs to £75 million – largely down to unrealistic costings and more work required than expected, according to the National Audit Office – but now the first half of a two-year trial is complete.

And independent surveys suggest that despite the delay and spiraling cost, the tram-train has proven perfectly popular, with a 100 per cent user satisfaction score. (The research conducted by passenger group Transport Focus was taken immediately after the service’s launch last year; a subsequent one is due in early 2020).

It’s no wonder the project is popular. Aside from being a novel form of transport — who doesn’t want to ride a tram-train? — the route links previously unconnected areas. Previously, residents of Rotherham could make the journey via a combination of train and tram, but a change was required to get into the centre of Sheffield, which is up a steep hill from the train station.

“Having entirely separate light rail and heavy rail networks that do not connect can mean that passengers have to change vehicles and absorb waiting times between destinations,” says Fiona Ferbrache, a lecturer at the University of Oxford’s Transport Studies Unit. “Tram-trains often provide new routes and connections, and can reduce the number of changes travellers have to make between different transport modes, which can help to create a more seamless journey.”

The South Yorkshire project was funded by the Department for Transport, with an eye to setting up tram-trains elsewhere, but the project is run by the South Yorkshire Passenger Transport Executive (SYPTE) and Stagecoach, the local tram operator, as well as National Rail and Network Rail on the, well, rail side.

So what are the tram-trains themselves? Seven Citylink Class 399 vehicles, made by Stadler, run on the line. They can run at speeds of up to 100km/hr – though don’t travel at such top speeds on this route – are bi-directional, so no turning is required, and are kitted out with dual-systems for safety, comms and controls, so they work across both the tramways and the railways.

“There’s specific kit that you wouldn’t normally need on our trams… but we needed these vehicles to be dual-compatible between the tramway and the railway,” says Tim Bilby, managing director of Stagecoach Supertram. “That’s why these are a bit special.”

How special? Bespoke wheels were designed that ensure the vehicle can operate on both tram and train lines. To be roadworthy on the tramway section, they require traffic indicators, horns, and rear-view cameras, but to work on mainline networks, they require what’s known as a train protection and warning system (TPWS) as well as support for signalling.

The tram-trains must carry the radio communications used on the trams as well as the GSM-R system used in trains, and meet both network’s differing safety requirements. Jose Carlos Redondo, technical project manager of the Project Citylink Sheffield for Stadler, says even the lights need dual systems. “When running a tram, you need [indicator] lights like a car,” he explains — but it’s confusing to run something that looks like a car down train tracks, so extra lights were added that can be flipped on to make it look like a train. Doubling up on systems to make the vehicle operate on both networks means the vehicles are more expensive than a standard train or tram vehicle.