A tram-train, also known as a dual-system tram,[1] is an interoperable urban rail transit system in which specially designed vehicles operate as trams on urban street-level networks and as trains on mainline railway tracks, alongside mainline trains.[2]
By complying with both light rail and heavy rail technical and safety standards, these vehicles can use existing tram infrastructure as well as railway lines and stations, enabling a single service to operate across both networks.[3] A tram-train combines the urban accessibility of a tram or light rail with a mainline train's greater speed in the suburbs.[4]
The modern tram-train concept was pioneered by the German city of Karlsruhe in the late 1980s,[5] resulting in the creation of the Karlsruhe Stadtbahn. This concept is often referred to as the Karlsruhe model,[4] and it has since been adopted in other cities such as Mulhouse in France[4] and in Kassel, Nordhausen and Saarbrücken in Germany.[5] It can be regarded as an evolution of the earlier interurban operations model.
An inversion of the concept is a train-tram – a mainline train adapted to run on-street in an urban tramway, also known as the Zwickau Model.
The tram-train often is a type of interurban[6] — that is, they link separate towns or cities, according to George W. Hilton and John F. Due's definition.[7]
Most tram-trains are standard gauge, which facilitates sharing track with main-line trains. Exceptions include Alicante Tram and Nordhausen, which are metre gauge.
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 a stop the emergency brakes are applied.
The idea is not new; in the early 20th century, interurban streetcar lines often operated on dedicated rights-of-way between towns, while running on street trackage in town. The difference between modern tram-trains and the older interurban and radial railways is that tram-trains are built to meet mainline railway standards, rather than ignoring them. A few interurban services did share tracks with mainline steam railroads, such as the Daisy Line or East Bay Electric Lines.
In 1924, in Hobart, Australia, sharing of tracks between trams and trains was proposed.[8]
| Country | Location | System | Year opened | Lines | Stations | Length | Notes |
|---|---|---|---|---|---|---|---|
 Austria | Gmunden | Traunsee Tram | 21 March 1912 | 1 | - | 17.9km (11.1miles) | Since (1 September 2018)[9] it has been connected to the Gmunden Tramway as part of the Traunseetram tram-train service.[10] |
| Vienna | Badner Bahn | 1873 | 1 | 36 | 30.4km (18.9miles) | Baden bei Wien | |
 Denmark | Aarhus | Aarhus Letbane | 21 December 2017 | 2 | 51 | 110km (70miles) | Tram-train and light rail[11] |
 France | Lyon | Rhônexpress | 9 August 2010 | 1 | 4 | 23km (14miles) | |
| Tram-train de l'ouest lyonnais | 22 September 2012 | 2 | 23 | 55km (34miles) | |||
| Mulhouse | 12 December 2010 | Line 3 | 18 | 22km (14miles) | Tram of Mulhouse tramway and Mulhouse Thur Valley Tram-train[12] | ||
| Nantes | Nantes tram-train | 15 June 2011 | 2 | 18 | 64km (40miles) | ||
| Paris, Île-de-France | Île-de-France tramway Line 4 | 20 November 2006 | line 4 | 20 | 13.3km (08.3miles) | ||
| Île-de-France tramway Line 11 Express | 1 July 2017 | Line 11 | 7 | 11km (07miles) | |||
| Île-de-France tramway Line 12 Express | 10 December 2023 | Line 12 | 16 | 20km (10miles) | |||
| Île-de-France tramway Line 13 Express | 6 July 2022 | Line 13 | 12 | 18.8km (11.7miles) | |||
| Île-de-France tramway Line 14 | March 2025 | Line 14 | 5 | 9.9km (06.2miles) | |||
 Germany | Chemnitz | City-Bahn Chemnitz | 10 March 1997 | 4 | - | - | |
| Karlsruhe | Karlsruhe Stadtbahn | 25 September 1992 | 12 | 190 | 262.4km (163miles) | ||
| Kassel | Kassel RegioTram | 2006 | 3 | - | 184km (114miles) | ||
| Nordhausen | Trams in Nordhausen | 25 August 1900 | 3 | 32 | 22.4km (13.9miles) | ||
| Saarbrücken | Saarbahn | 24 October 1997 | 1 | 43 | 44km (27miles) | ||
 Hungary | Szeged, Hódmezővásárhely | Szeged-Hódmezővásárhely tram-train | 29 November 2021 | 1 | 31.6km (19.6miles) | ||
 Italy | Bergamo | Bergamo–Albino light rail | 24 April 2009 | 1 | 16 | 12.5km (07.8miles) | |
| Rome | Rome–Giardinetti railway | 1916 | 1 | 19 | 5.4km (03.4miles) | Closed; 2015 (Centocelle-Giardinetti) | |
| Sassari | Metrosassari | 27 October 2006 | 1 | 8 | 4.331km (02.691miles) | ||
 Netherlands | The Hague-Rotterdam | RandstadRail | 29 October 2006 | 4 | 73 | 71km (44miles) | |
 Portugal | Porto | Porto Metro Line B/Bx - (Estádio do Dragão – Póvoa de Varzim) | 13 March 2005 | 1 | 36 | 33.6km (20.9miles) | Bombardier Flexity Swift light rail |
| Porto Metro Line C - (Campanhã – Ismai) | 30 July 2005 | 1 | 24 | 19.6km (12.2miles) | |||
 Spain | Alicante | Alicante Tram Line 1 (Alicante Metropolitan Tram - Luceros – Benidorm) | 30 July 2007 | 1 | 20 | 19.6km (12.2miles) | |
| Alicante Metropolitan Tram - Luceros – El Campello | 2003 | 1 | 17 | 14.404km (08.95miles) | |||
| Mallorca | Mallorca rail network, Serveis Ferroviaris de Mallorca | 1994 | 3 | 29 | 85km (53miles) | Ferrocarril de Sóller | |
| Cádiz | Cádiz Bay tram-train | 26 October 2022 | 1 | 21 | 24km (15miles) | ||
 United Kingdom | Sheffield - Rotherham | South Yorkshire Supertram | 25 October 2018 | 1 | 14 | 29km (18miles) | Tram-Train (Black) Route |
| Cardiff & South Wales Valleys | South Wales Metro | 2026 | 9 | 94 | 169.2km (105.1miles) |
| Country | Location | System | Year opened | Lines | Stations | Length | Notes | |
|---|---|---|---|---|---|---|---|---|
 Canada | Ottawa | Line 2 (O-Train) | 15 October 2001 | 1 | 11 | 19km (12miles) | ||
| Line 4 (O-Train) | 6 January 2025 | 1 | 3 | 4km (02miles) | ||||
| Waterloo Region | Ion rapid transit[13] | 21 June 2019 | 1 | 19 | 19km (12miles) | |||
 Mexico | Puebla | Puebla–Cholula Tourist Train | 23 January 2017 | 1 | 2 | 17.4km (10.8miles) | (Closed; 31 December 2021; trains now sold to Tren Interoceánico) | |
 United States | San Diego, California | San Diego Trolley | 26 July 1981 | 4 | 62 | 105km (65miles) |
Models of tram designed for tram-train operation include:
See also: Street running train.
Capital MetroRail – commuter rail that shares more commonality with train-tram operation, with downtown street running and usage of mainline track. Uses diesel multiple units.
