- "Tram-train" redirects here. For the Siemens-Duewag train-tram, see RegioSprinter.
A tram-train is a light-rail public transport system where trams run through from an urban tramway network to main-line railway lines which are shared with conventional trains. This combines the tram's flexibility and accessibility with a train's greater speed, and bridges the distance between a main railway stations and a city centre.
There is also a train-tram, which is a train modified to also run on tramlines. Generally, the tram-train and train-tram are interchangeable, although a train-tram is based on a train design modified to also run as a tram and a tram-train is based on a tram design modified to also run on a train line.
The tram-train concept was pioneered with the Karlsruhe model in Germany, and has since been adopted on projects such as the RijnGouweLijn in the Netherlands, at Mulhouse in France and in Kassel and Saarbrücken in Germany.
Most tram-trains are standard gauge, which facilitates sharing track with main-line trains. Exceptions include Alicante Tram and Nordhausen which are metre gauge, and the 950 mm gauge Sassari Tram-train.
Tram-train vehicles are dual-equipped to suit the needs of both tram and train operating modes, with support for multiple electrification voltages if required and safety equipment such as train stops and other railway signalling equipment. The Karlsruhe and Saarbrücken systems use ‘PZB’ or ‘Indusi’ automatic train protection, so that if the driver passes a signal at stop the emergency brakes are applied.
The idea is not new: in the early 20th century, interurban streetcar lines often operated on the same tracks as steam trains, until crash standards prevented track sharing. In 1924, in Hobart, Tasmania, sharing of tracks between tram and train was proposed.
The difference between modern tram-trains and the older interurbans and radial railways is that tram-trains are built to meet mainline railway standards, rather than ignoring them. An exception is the USA's River Line in New Jersey which runs along freight tracks with time separation: passenger trains run by day, and freight by night.
Existing systems 
- Alicante Tram, Alicante, Spain
- Chemnitz, Germany - 750 V DC
- Kassel, Germany (2006)
- Nordhausen, Germany - 600 V DC/on-board diesel engine
- Nantes, France (Nantes-Clisson, SNCF)
- Paris, France (Line T4, SNCF)
- Mulhouse tramway, Mulhouse, France
- Saarbrücken, Germany
- Sassari Tram-train, Sassari, Italy
- Stadtbahn Karlsruhe, Karlsruhe, Germany - 750 V DC/15 kV AC
- RandstadRail, The Hague, Netherlands
- Zwickau, Germany - on-board diesel engine (Light-weight RegioSprinter diesel railbuses that also operate on street tramway)
North America 
- Capital MetroRail in Austin, Texas, USA - commuter rail that shares more commonality with tram-train operation, with downtown street running and usage of mainline track. Uses diesel multiple units.
- River Line (New Jersey, United States) - diesel multiple units.
- The O-Train in Ottawa, Canada which uses European-style main line trains, and the Newark City Subway extension in Belleville and Bloomfield, New Jersey (with an FRA-imposed time-share waiver) do not qualify it as a tram-train per se, whose chief characteristic is shared-use of main-line tracks at all times.
Proposed systems 
- Aarhus Letbane, Denmark
- Braunschweig, Germany
- Bratislava, Slovakia
- Grenoble, France
- Groningen, Netherlands
- Kiel, Germany
- Košice, Slovakia
- León, Spain
- Liberec — Jablonec nad Nisou, Czech Republic
- Linköping, Sweden
- Lyon, France
- Manresa, Catalonia, Spain
- Metro Mondego, Coimbra, Portugal
- Midland Metro extensions in the West Midlands conurbation, England
- Porto Metro Lines B and C, Porto, Portugal
- RijnGouweLijn, Netherlands
- Metro de Sevilla: - Seville has one metro line and one tram line that are not connected, but the long-term intention is to link the metro and tram systems
- Strasbourg, France
- Szeged, Hungary
- TramCamp, Camp de Tarragona, Catalonia, Spain
- Wrocław, Poland (2005) — 600 V DC/3 kV DC
- Riga, Latvia
United Kingdom 
In March 2008 the UK Department for Transport had released details of a plan to trial diesel tram-trains on the Penistone Line for two years starting in 2010. There was no commitment to connect them to the Sheffield tram network, and in September 2009 the idea was withdrawn as it was deemed not economically viable for a trial due to the cost of the extra development required for the diesel engines to meet the forthcoming stringent EU emission regulations. Instead single-voltage electric tram-trains will be trialled between Rotherham and Sheffield.
A tram-train trial in the Manchester area was ruled out as the Department for Transport wanted to try low-floor tram-trains, whereas Manchester Metrolink cars have high floors.
In August 2009 the Liverpool Daily Post reported that a new Merseyrail tram-train link to Liverpool John Lennon Airport was under consideration. The Merseyrail Northern Line and the City Line between Liverpool Lime Street and Liverpool South Parkway were being assessed. From South Parkway the tram-trains would transfer seamlessly to a new tramway. A link from Edge Hill in the east of the city to the Arena at Kings Dock near the city centre was also being considered.
Other suggested schemes for England include:
- Stourbridge — Dudley — Walsall
- Leeds — Harrogate — York
- Leeds — Wakefield
- Leeds — Bradford Interchange — Bradford
- Leeds — Selby
- Manchester — Marple 
- Manchester — Northwich (via the direct Manchester Metrolink line to Altrincham)
- Norwich — Rackheath
- Tees Valley Metro (later phases)
- Abbey Line (Watford Junction to St Albans Abbey)
- Thanet Light Rapid Transit, Kent
- Medway Metro / MedRail, Kent — project now "mothballed"
- Adelaide, South Australia – On June 5, 2008, the Government of South Australia announced plans for train-tram operation on the Adelaide Metro's Outer Harbor/Grange train lines and City West-Glenelg tramline extension as part of a 10-year A$2 billion public transport upgrade.
Models of tram designed for tram-train operation include:
- Alstom’s Dualis, derived from the Citadis
- Bombardier’s Flexity Link
- Bombardier-Adtranz A32.
- Siemens' Avanto (also called S70)
- Vossloh Citylink NET
See also 
- "TRAMS AND TRAINS.". The Mercury (Hobart, Tas. : 1860 - 1954) (Hobart, Tas.: National Library of Australia). 12 February 1924. p. 6. Retrieved 21 April 2012.
- Haydock, David (April 2011). "France's first real tram train". Today's Railways (Platform 5 Publishing Ltd). pp. 37–40.
- "Aarhus tram-train project gets the go-ahead". Railway Gazette International. 10 May 2012.
- "Rotherham tram-tram project funding confirmed". Railway Gazette International. 17 May 2012.
- "First tram-trains get go-ahead for Sheffield and Rotherham". BBC News. Retrieved 17 May 2012.
- "Britain announces tram-train trials". Railway Gazette International. 18 March 2008.
- "Tram-train line given go ahead". South Yorkshire Transport Forum.
- "Item 10 Rail Issues" (pdf). Transport for Greater Manchester Committee. 1 February 2008.
- "Tram link bid for Liverpool airport". Liverpool Daily Post. 3 August 2009. Retrieved 20 August 2009.
- "Tees Valley Metro". Darlington Transport Forum. 6 October 2008. Retrieved 29 December 2008.
- "St Albans Abbey tram-train announced". Railway Gazette International. 30 October 2009.
- TramTrain - the 2nd generation: Searching for the ‘ideal’ TramTrain-city
- New TramTrain for Mulhouse - Reportage and images (english/german.)
- Construction of the TramTrain system in Mulhouse with images (english/german.)
- tram-train of Karlsruhe transformed in a subway in the center
- Leeds City Region proposal
- (Jane's) Urban Transit Systems