Stadler Citylink

The Stadler Citylink (known as the Vossloh Citylink until 2015) is a series of tram-trains manufactured by Stadler Rail at its Valencia factory since 2011. The design was introduced by Vossloh España before their takeover by Stadler Rail in 2015. They are currently used in Germany, Hungary, Mexico, Spain and the United Kingdom, with more on order in Austria. Stadler opened a new factory in the United States in 2016, which is in the process of building up to 80 Citylink vehicles for service in Salt Lake City beginning in 2028.

The Class 399 variant was placed into service on the Sheffield Supertram network from September 2017 as the United Kingdom's first tram-train; following the success of this trial, the Class 398 variant has been ordered and is due to enter service on the South Wales Metro from 2025. The largest order to date for Citylinks was placed as part of the VDV Tram-Train Project in January 2022, with a consortium of six Austrian and German operators ordering 246 vehicles with an option to order a further 258 afterwards. The deal is worth €4 billion (£3.3 billion), and is the largest contract in Stadler's history.

The Stadler Citylink is available over a range of lengths, from two to four carriages long; the most commonly-produced model is 37 m (121 ft) long and 2.65 m (8.7 ft) wide with three carriages, and the longest variants can be built up to 50 m (160 ft) long for additional capacity. They can also be produced to a variety of different track gauges, with models produced for metre gauge networks in Mallorca, Alicante and León, standard gauge networks in the United Kingdom and mainland Europe.

Specifications vary depending on the operator; for example, the Citylinks operating in Sheffield are equipped internally similarly to the city's existing trams, due to the relatively short length of the tram-train extension to Rotherham, while Citylinks that operate over longer distances can be equipped with facilities such as toilets and luggage racks. Depending on the internal layout, Citylinks can have a capacity of up to 250 passengers.

The Citylink was designed as an electric multiple unit tram-train, with power drawn from overhead line equipment (OHLE) at 750 V DC or 1,500 V DC. Some Citylinks are fitted with transformers to provide dual-voltage capability, such as those used in Sheffield, which run at 750 V DC on the city's tram network, but with the ability to also use 25 kV 50 Hz AC in the future, as is standard for British railways. In Chemnitz, Citylinks are fitted with a diesel engine as well as 750 V DC overhead power to provide hybrid-electric capability; while vehicles sold in Mallorca and Mexico are fitted with a diesel engine only due to a lack of railway electrification. Citylinks have a top speed of 110 km/h (68 mph) when operating on interurban routes under electric power.

As of late 2025, the Stadler Citylink is operated in seven different systems across five different countries in Europe and North America, while a further seven systems in another four countries have the model on order or undergoing testing.

In January 2022, Schiene Oberösterreich (Schiene OÖ), operator of the Linzer Straßenbahn-Netz network in Linz, announced that they had ordered Stadler Citylinks for their network as part of the VDV tram-train consortium.

In January 2022, the state government of Salzburg (through arm's-length company Salzburg AG), operator of the Salzburg S-Bahn, announced that they had ordered Stadler Citylinks for their network as part of the VDV tram-train consortium.