Sheffield City Region Mayor, Dan Jarvis and then Transport Minister, Jo Johnson formally launched the service at Rotherham Parkgate, before travelling to Sheffield Cathedral on board tram-train 204. The line to Parkgate is the first extension to the South Yorkshire Supertram network since it opened in 1994.

The tram-train concept involves combining the flexibility of trams – the ability to access urban centres through street running, negotiating tight corners, steep inclines etc – with the opportunity to run longer distances at higher speeds on heavy rail lines. The system was pioneered in Karlsruhe, Germany in the late 1980s and has proved an enormous success. The model has subsequently been copied in cities across the globe.

The South Yorkshire tram-train scheme – the first such undertaking in the UK – is officially an experiment by the Department for Transport, designed to prove the technology. This was unnecessary as the technology had already been proven in Karlsruhe and elsewhere. Originally due to start in December 2015, the project has been beset by poor decision-making and delays due to the lack of clear objectives and so its original capital budget of £15 million has turned into an actual cost of £75 million.

DfT is funding the operation for its first two years. South Yorkshire PTE hopes to enter into an agreement with Stagecoach to operate the service for a further four years, finishing to coincide with the end of Stagecoach’s concession to operate the tramway network in 2024.

Tram-trains operate from Cathedral tram stop in Sheffield city centre along the existing `yellow route’ tram line towards Meadowhall, as far as Meadowhall South. Here, they diverge onto a new Tinsley chord, which connects the tram line to the adjacent former Great Central Railway line from Woodburn Junction to Rotherham Central. All tram-trains pause briefly on the chord while the driver changes from tram mode to train mode (and vice-versa in the reverse direction), before proceeding to Rotherham Central. Unlike Manchester Metro, Supertram uses low floor vehicles so that there are no platforms on the street sections; the tram-train vehicles are also low-floor so two new low-height tram-train only platforms have been added at the south end of Rotherham Central station, essentially extensions of the heavy rail platforms but numbered 3 and 4. Tram-trains continue for just over a mile further to a new terminus at the Parkgate retail complex, on a short spur to the north side of the former GC line.

Service consists of three trams per hour, timed to depart at xx.01, xx.27 and xx.39 from Cathedral; xx.09, xx.31 and xx.59 from Parkgate, Monday to Saturday. Three tram-trains per hour also operate on Sundays, although at slightly different timings. The slightly irregular intervals are because of the need to fit around Northern heavy rail services and occasional freights on the section through Rotherham Central. Journey times between Cathedral and Parkgate are 26/27 minutes, giving scheduled turn around times of 2–5 minutes. Tram-trains operate from around 0530–2230 from Monday to Saturday and 0900–1800 on Sundays. Although colours are used to denote existing tram routes (yellow, blue, purple), the Parkgate route is described simply as TT both in the timetable and on tram-train destination indicators.

Seven new tram-train vehicles were built by Vossloh (now Stadler) in Valencia, Spain in 2015–16. Numbered 201–207 (Network Rail 399 201-207), they have a maximum speed of 50 mph in tram mode and 55 mph in train mode. Three tram-trains are required to provide the service to Parkgate, plus one spare; the other three vehicles supplement the original network.

Whilst of similar appearance to the original Siemens trams, being articulated in three sections, the tram-trains can work from both 750 V DC or 25 kV AC 50 Hz overhead supply. Despite the whole point of tram-train being compatibility with the main line network, Network Rail decided to electrify on 750V DC, encountered massive interference issues and hence cost, but wanted to persist in order to learn about 750V DC. This was not a credible approach - electrifying the Network Rail section at 25kV AC would have been so much simpler and cheaper - so we have a worst case scenario of passive provision for 25kV AC to future-proof the route should the line from Sheffield to Doncaster be electrified. Much of the escalation in cost can be put down to the poor decisions for this element of the scheme.

The tram-trains are divided into two separate operating pools. Street sections of Supertram have grooved rails that cannot be negotiated by the broader wheel profiles required by Network Rail, and conversely, narrower tram wheels are not compatible with NR switch blades. Hence, the four tram-trains fitted with NR-compatible wheel profiles can only operate from Sheffield city centre as far as Shalesmoor and Spring Lane on the blue and purple routes, to where the grooved rail has been replaced. The other three tram-trains cannot venture from the original tram network. Tram-trains can only move between pools by having their bogies switched; there is a spare set of NR-compatible bogies. Initially tram-trains 201–204 were allocated to the Parkgate route, but following an unfortunate collision with a lorry on the first day of public service, 204 has been replaced by 206 using the spare set of bogies.

It should be noted that Supertram byelaws are applicable to the tram-train service, rather than the national rail byelaws. As such, dogs (other than assistance dogs) and bicycles cannot be carried on tram-train services.

Tram-trains should not be considered as a cheap alternative to heavy rail - tram-train vehicles have to be able to work with multiple signalling and power supply systems so are likely to be more expensive than heavy rail vehicles. That doesn’t mean that the costs of the Rotherham experiment will be replicated elsewhere, provided that clear objectives are set and managed by an intelligent client. The thing about tram-train is that they can co-exist with freight and heavy and fast passenger trains, whereas light rail cannot.

Although the DfT is still regarding this project as an experiment, developments are already taking place elsewhere in the UK. Greater Manchester has aspirations for tram-train extensions to the Metrolink network, DfT has required MetroWest to consider tram-trains for Portishead reopening and Transport for Wales has recently ordered 36 new `Metro’ vehicles intended for on-street running to a new station in the Cardiff Bay area. Railfuture advocates a tram-train solution where the benefits of bringing passengers from the wider rail network directly into the city centre and distributing them around the city justify the extra cost.

Travel South Yorkshire

Tram train pilot

Railfuture press release

Wales and Borders award article including planned tram-train service