A Nordhausen "DUO" Combino on the track linking the urban tramway, where it is electrically powered via overhead wires, and the HSB (Harzer Schmalspurbahn) rural railway, where it is powered by an onboard diesel engine

The Zwickau Model has main-line lightweight diesel tram-trains running through urban streets. Because the trams are metre gauge and the trains standard gauge the shared tracks are dual-gauge, with one shared rail and one exclusive rail for each.

A tram-train is a light-railpublic 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 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.

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 dedicated rights-of-way between towns, while running on street trackage in town. In 1924, in Hobart, Tasmania, sharing of tracks between trams and trains was proposed.[3]

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 United States' River Line in New Jersey which runs along freight tracks with time separation: passenger trains run by day, and freight by night.

UTA TRAX uses former Denver and Rio Grande tracks as well as street trackage to service Salt Lake City. Between the hours of midnight and six in the morning, Union Pacific freight trains use much of the trackage, up to just past 2500 S to service a number of industries along the line.

Sprinter uses track also used by BNSF for freight at night in the Escondido branch and also share track with Coaster Metrolink and Amtrak

Erlangen, Germany – an extension of Straßenbahn Nürnberg not initially planned to use mainline rail tracks but proposed to do so in the future. The planned line to Herzogenaurach replicates a former mainline rail line

île de France (Paris region), France. The system is called Tram Express by the transport authority STIF: 1 line already exists (Tramway Line 11 Express) and 2 lines are scheduled (Tramway Lines 12 Express and 13 Express). The light train rolling stock will only roll on national rail network in western line (Line 13 Express) a short section of 3.6 km (2.2 mi) is an urban tram section of the 19 km (11.8 mi) line. The southern line (Line 12 Express
) is a 20 km (12.4 mi) line, 10 km will be tram section and the 10 km another will roll on national rail network.

In March 2008 the UK Department for Transport released details of a plan to trial diesel tram-trains on the Penistone Line for two years starting in 2010.[11] 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.[12]

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.[13]

1.
Tram
–
A tram is a rail vehicle which runs on tracks along public urban streets, and also sometimes on a segregated right of way. The lines or networks operated by tramcars are called tramways, Tramways powered by electricity, the most common type historically, were once called electric street railways. However, trams were used in urban areas before the universal adoption of electrification. Tram lines may run between cities and/or towns, and/or partially grade-separated even in the cities. Very occasionally, trams also carry freight, Tram vehicles are usually lighter and shorter than conventional trains and rapid transit trains, but the size of trams is rapidly increasing. Some trams may also run on railway tracks, a tramway may be upgraded to a light rail or a rapid transit line. For all these reasons, the differences between the modes of rail transportation are often indistinct. In the United States, the tram has sometimes been used for rubber-tired trackless trains. Today, most trams use electrical power, usually fed by a pantograph, in some cases by a sliding shoe on a third rail. If necessary, they may have dual power systems — electricity in city streets, trams are now included in the wider term light rail, which also includes segregated systems. The English terms tram and tramway are derived from the Scots word tram, referring respectively to a type of truck used in coal mines and the tracks on which they ran. The word tram probably derived from Middle Flemish trame, a Romanesque word meaning the beam or shaft of a barrow or sledge, the identical word la trame with the meaning crossbeam is also used in the French language. The word Tram-car is attested from 1873, although the terms tram and tramway have been adopted by many languages, they are not used universally in English, North Americans prefer streetcar, trolley, or trolleycar. The term streetcar is first recorded in 1840, and originally referred to horsecars, when electrification came, Americans began to speak of trolleycars or later, trolleys. The troller design frequently fell off the wires, and was replaced by other more reliable devices. The terms trolley pole and trolley wheel both derive from the troller, Modern trams often have an overhead pantograph mechanical linkage to connect to power, abandoning the trolley pole altogether. Conventional diesel tourist buses decorated to look like streetcars are sometimes called trolleys in the US, the term may also apply to an aerial ropeway, e. g. the Roosevelt Island Tramway. Over time, the trolley has fallen into informal use

2.
RegioSprinter
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The RegioSprinter is a German diesel railcar built by Siemens-Duewag for rapid regional railway services. Originally the RegioSprinter was designated as a Regional Combustion-engined Railbus by Duewag AG, developed as prototypes for fast regional railway services on the plains, the RegioSprinter still has the fastest acceleration of any multiple unit or railbus in Germany. Due to several technical and conceptual defect, however, only few were built. Based on their experience with the Regiosprinter Siemens developed its successor, the Desiro, in 1999, all the Vogtlandbahn vehicles were converted to meet tramway regulations, in order to be able to transfer to a tram line in the centre of Zwickau. The vehicles are designed with three sections, in the two, single-axled end modules are the drivers cabs and the drive units like those on trams. In the middle is a twin-axled, unmotored module, two thirds of the vehicle has a low floor. The seats are arranged in a 2+3 configuration, there is no due to the short journey distances envisaged. Late the Vogtlandbahn had to fit all its vehicles with toilets, in 1995 the Dürener Kreisbahn bought a total of 17 RegioSprinter for the Rurtalbahn, which were deployed to the two sections of line radiating from Düren, replacing the Uerdingen railbuses. From 1996 the Vogtlandbahn bought a total of 18 vehicles for use on the lines from Zwickau to Adorf/Vogtl. because the completion of these routes was repeatedly delayed after their refurbishment, the new vehicles initially worked the line from Zwickau to Bad Brambach. At present the railbuses are in services on the following Vogtlandbahn lines, – Zwotental – Klingenthal – Kraslice VB2 Zwickau Hbf – Reichenbach ob Bf – Herlasgrün – Plauen ob Bf – Adorf/Vogtl. – Mehltheuer – Plauen ob Bf – Herlasgrün – Falkenstein/Vogtl, – Zwotental – Adorf Until the timetable change in December 2006 the Vogtlandbahns RegioSprinters were also on duty on the VB7 line between Schönberg/Vogtland and Schleiz West. Services on this route were withdrawn on 9 December 2006 by the public transport company of the free state of Thuringia. Moreover, in 2006 two of the railbuses were hired to the Prignitz railway, which used them on their lines in the western Ruhrgebiet due to a shortage of stock. In 1999 the Nærumbanen in the Copenhagen area bought four RegioSprinter railbuses, since 2002 operations have been run by Lokalbanen A/S, which took over several smaller railway companies in the Copenhagen area. The railbuses were owned at the time by the Hovedstadens Lokalbaner, which hired them to the LB

3.
Street running
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On-street running or street running is the routing of a railroad track or tramway track running directly along public streets, without any separation. The rails are embedded in the pavement, and the train shares the street directly with pedestrians. Trains generally travel at reduced speed for safety reasons, if there are stations on the section, they can appear similar in style to a tram stop, but often lack platforms, pedestrian islands, or other amenities. Passengers may be required to wait on a distant sidewalk, and then to board or disembark directly among mixed traffic in mid-pavement, rather than at curbside. Although bridges and tunnels are not streets, rails can still be embedded in the surface of bridges and this is also considered to be street running. This list does not include conventional tram, interurban, light rail or the tram portions of tram-train systems, over the Salto Grande Dam, between Concordia, Argentina and Salto, Uruguay. Bridge between Viedma, Río Negro and Carmen de Patagones, Buenos Aires, the North Coast main line runs down Denison Street in Rockhampton, Queensland carrying freight and passenger services. A sugar-cane railway runs down Mill Street, uruguaiana, almost 300 m. in the Vasco Alves street to reach the Paso de los Libres–Uruguaiana International Bridge. Notable examples in Canada include, Brantford, Ontario Clarence Street Guelph, Ontario Kent Street, CNR, near Mannheim, the Oberrheinische Eisenbahn and Rhein-Haardt-Bahn are street running through several villages. In Linkenheim, near Karlsruhe, the Hardt Railway was changed to BOStrab in 2011 for that reason, Road and rail share the Lindaunis Bridge in Schleswig-Holstein. Freight trains using the infrastructure of Rhein-Sieg-Verkehrsgesellschaft to the company Evonik in Niederkassel-Lülsdorf passing the village Sieglar are running inside the Pastor-Böhm-Straße, one of the most famous locations is when the steam-powered Darjeeling Himalayan Railway Toy train squeezes between narrow shop fronts down past a bazaar in India. Indonesia used to have an extensive steam tramways network, which had street running sections in various towns and cities in Java. Two sections remain in use in 2010, part of the Wonogiri branch runs along the Slamet Riyadi street in Surakarta, the earlier line sees both passenger and freight service, while the other line is exclusively for freight. Freight trains to and from the docks at Dublin share the Alexandra road with cars The Bernina Railway runs in the streets of Tirano, the Circumetnea ran until 1999 on the Corso delle Provincie in Catania. The Cremona–Iseo railway ran until 1956 in the street of Cavatigozzi. The Domodossola–Locarno railway started until the 1980s from the square of Domodossola. The Rivabahn was until 1981 a freight railway that ran into the city of Trieste along the seaside street, the Rome–Fiuggi railway runs completely along the Via Casilina in Rome. This railway serves as the only way of reaching Machu Picchu from Cusco without walking

4.
Heilbronn
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Heilbronn is a city in northern Baden-Württemberg, Germany. It is surrounded by Heilbronn County and, with approximately 123,000 residents, the city on the Neckar is a former Imperial Free City and is the seat of Heilbronn County. Heilbronn is also the center of the Heilbronn-Franken region that includes most of northeast Baden-Württemberg. Heilbronn is known for its industry and is nicknamed Käthchenstadt. Heilbronn is located in the corner of the Neckar basin at the bottom of the Wartberg. It occupies both banks of the Neckar, and the highest spot inside city limits is the Schweinsberg with a height of 372 meters, Heilbronn is adjacent to Swabian-Franconian Forest Nature Park and is surrounded by vineyards. Heilbronn and its surroundings are located in the part of the larger Stuttgart metropolitan area. The city is the center of the Heilbronn-Franken region and is one of fourteen such cities in the Baden-Württemberg master plan of 2002. The city is divided into nine boroughs, The oldest traces of humans in, the fertile Neckar floodplains in the Heilbronn basin aided early settlement by farmers and ranchers. The city limits of present-day Heilbronn contain many sites of Bronze Age finds, later on, but still before AD, the Celts already mined here for salt from brine. Under Roman Emperor Domitian the Romans pushed east away from the Rhine, a castle in todays borough of Böckingen was part of that limes, and nearby numerous Roman villas and plantations were built. Around 260, the Romans surrendered the limes, and the Alamanni became rulers of the Neckar basin, between the 4th and 7th centuries, the area became part of the Frankish Empire, and the first settlement was built in the general vicinity of the present center of town. In 741 Heilbronn is first mentioned in a document of the Diocese of Würzburg as villa Helibrunna. The name Heilbrunna hints to a well that is located not far from the basilica, in 1225 Heilbronn was incorporated into the Hohenstaufen Empire as oppidum Heilecbrunnen. Oppidum signified a city fortified by parapet and trenches, later during the 13th century, the Teutonic Knights obtained ownership of a large area south of Heilbronn which would remain owned by that order until German Mediatisation in 1805. Starting in 1268, the built the Deutschhof there as one of its residences. After the demise of the Staufen dynasty, King Rudolf I returned city status to Heilbronn in 1281, in addition to the advocate he put a council in place that was headed up by a mayor. Around 1300, the first city hall was erected in the market place, the Neckar privilege gave the city the right to modify the flow of the river in 1333, which meant it now had the right to construct dams, harbors and mills

5.
Kassel RegioTram
–
The RegioTram is a 184-kilometer tram-train light rail system in Kassel, Hesse, Germany. Kassels tram-train system follows the Karlsruhe model, and has been in operation since 2007. The operator of the RegioTram network was, until December 2013, RegioTram mbH, in addition, the Nordhessische Verkehrsverbund is involved in the organization of RegioTram. Since 9 December 2013, Kassels RegioTram is operated by a consortium of Kasseler Verkehrs-Gesellschaft, the implementation of the RegioTram project includes various interlocking measures to improve local public transport in Kassel. The core component of the Kassel RegioTram project is a newly created link between the two systems at the Kassel Hauptbahnhof. The development of the required to allow for a 30-minute headways on all lines will be implemented by 2014 at the earliest. Kassel is served by the four lines of the RegioTram system, RegioTram operates using 28 tramcars from Alstom RegioCitadis delivered in 2004. Similar vehicles of the model are also in use on RandstadRail in the Netherlands. Preliminary operations started on 10 June 2001, initially with six borrowed Saarbahn tramcars, thus, the previous regional railway timetable was now being served by the new vehicles. RegioTram operation with 30-minute headways was realized, RegioCitadis type vehicles manufactured by Alstom in Salzgitter were delivered in July 2004, and took over the operation on this line on 8 May 2005, the borrowed Saarbahn tramcars were then returned. This route is now served by RegioTram Line 3, starting on 29 January 2006, the first RegioTram operations began on the Kassel tram rail network itself. The hybrid RegioTram vehicles joined the tram tracks in the core of Kassel on the Lossetalbahn to Hessisch Lichtenau during peak hours. The diesel-electric vehicles used a route over the Waldkappel rail line between Ober- and Nieder-Kaufungen which is not electrified. This meant, in contrast to the trams which served all stops, in August 2007, the switch to the continuous use of conventional tramcar vehicles on this line was made. The former tram-train runs over the railway through Waldkappel were replaced by tram express trips that do not operate at all stops along the route. Starting 1 June 2006, RegioTram operations from Kassel Hauptbahnhof, through Baunatal, Guxhagen and Körle, to Melsungen and this RegioTram Line 5 runs alternately once and twice every hour. Operations between Kassel and Wolfhagen, through Ahnatal and Zierenberg, began on 10 December 2006 on RegioTram Line 4, between 16 September 2007 and the timetable change in December 2007, the RegioTram Line 9 operated in advance from Kassel Hauptbahnhof to Treysa. RegioTram routes in Kassel changed 19 August 2007,16 September 2007 and December 20097 from running to the Innenstadtring in downtown, the full development of the infrastructure to allow for a 30-minute headways on all lines will be implemented by 2014 at the earliest

6.
Alstom Citadis
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The Citadis is a family of low-floor trams and light rail vehicles built by Alstom. An evolution of Alstoms earlier TFS vehicle, most Citadis trams are made in Alstoms factories in La Rochelle, Reichshoffen and Valenciennes, France, and in Barcelona, Spain, also, Gaziantep bought second-hand TFSs from Rouen. The Citadis family includes both partial and fully low-floor trams and LRVs, in versions with three, five, seven, and nine sections, own Russian name according unifying system of rolling stock classification, 71-801. This train type can be built as a dual-voltage or electro-diesel vehicle with various configurations.5 to 5 km, a total of 31 sets have been ordered by the SNCF at an average cost of €3.2 million per train set. Like most trams, Citadis vehicles are powered by overhead electric wires collected by a pantograph. On the networks in France and in Sydney, the switch to conventional overhead wires in outer areas. Another option is to use batteries to store electrical power. The Citadis trams in Nice operate off a set of nickel metallic hydride batteries in two open spaces where overhead wires would be an eyesore

7.
Flexity Classic
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The Flexity Classic is a model of light-rail tram manufactured by Bombardier. Flexity Classic runs on standard gauge 1,435 mm as well as metre gauge 1,000 mm in Essen,1,450 mm in Dresden and 1,458 mm in Leipzig. It is used by a number of German cities, Norrköping and Stockholm, Sweden, in Kraków and Gdańsk, Flexity Classics were chosen to replace heritage trams used on the Glenelg tramline in Adelaide, Australia, as they are a proven design and have low maintenance requirements. The Flexity Classic’s closest competitors are Alstom’s Citadis, the Combino and Avanto from Siemens, in 2006, TransAdelaide now Public Transport Services as part of DTEI began to replace the H Type cars operating on their Glenelg tramway with a fleet of eleven Flexity Classic trams. The first of the new Flexitys was delivered to the Glengowrie depot in November 2005, delivery continued in small batches through 2006, with new trams operating the Glenelg line side-by-side with the H Type in the interim. They have a low floor throughout, except over the bogies. TransAdelaide continues to operate the Flexitys with roving conductors, although these are not now needed for operation of the cars. Unlike the H Type, Flexitys cannot be coupled into two-car sets at busy times, the internal layout is designed to accommodate wheelchairs and large numbers of standing passengers. The relative lack of seating, together with other minor teething problems, resulted in some adverse comments from commuters, the original unit 103 was destroyed during shipping. It is now held in storage at Transadelaides Glengowrie depot storage for spare parts, Bombardier subsequently delivered a replacement 103, and this was the final tram currently to be delivered. 4 more units 112 to 115 are on order and will enter service in a few years. The Flexity Classic XXL model was developed for the Dresden Transport Authority by the German factory Bombardier Transportation in Bautzen and it is 45 m long, runs on twelve axles and has a capacity of 260 passengers with 153 seats. The Flexity Classic XXL has, because of Dresdens altitude differences of 100 metres, the tram has been in service since 2003 and serves tram lines with a high peak load of passengers. The exterior is designed for the Dresden Transport Authority, which owns 43 trams. The Flexity Classic XXL is also in service in Leipzig, Germany with the Leipzig Transport Authority, although the exterior design is customized, the tram offers the same capacity. It has been in service since 2005, the LVB first ordered 12 trams of this type, then exercised an option for another 12 trams in September 2005 and a third batch of 9 was delivered in late 2011/early 2012

8.
Nordhausen
–
Nordhausen is a city in Thuringia, Germany. It is the capital of the Nordhausen district and the centre of northern Thuringia. Nordhausen is located approximately 60 km N of Erfurt,80 km W of Halle,85 km S of Braunschweig and 60 km E of Göttingen. Nordhausen was first mentioned in records in the year 927 and became one of the most important cities in central Germany during the later Middle Ages. The city is situated at Zorge river, a tributary of the Helme within the region of Goldene Aue at the southern edge of the Harz mountains. In the early 13th century, it became an imperial city, so that it was an independent. Due to its trade, Nordhausen was prosperous and influential. It was the third-largest city in Thuringia after Erfurt, todays capital, and Mühlhausen, Nordhausen was once known for its tobacco industry and is still known for its distilled spirit, Nordhäuser Doppelkorn. Industrialization accompanied railway construction that linked the cities to major markets in the mid-19th century, in the late 19th century, narrow-gauge railways were constructed in this region through the Harz mountains. In December 1898 the Nordhausen-Wernigerode Railway Company or NWE added a line, the Harz Narrow Gauge Railways are maintained today by local authorities and frequented primarily by tourists. In the early 20th century, this became a center of the engineering, during World War II, the Nazi German government established and operated the nearby KZ Mittelbau-Dora concentration camp, where 60,000 forced labourers had to work in the arms industry. They were prisoners of war and persons from occupied territories, some 20,000 persons died because of the bad conditions. In April 1945, most of the city was destroyed by Royal Air Force bombings, most of the historic buildings of the city were destroyed, it suffered the most damage during the war of any city in Thuringia. A week later the United States troops occupied the city, followed later by the Soviet Red Army. The city was within the Soviet zone of occupation, and later the territory was known as East Germany, hundreds of German scientists and their families from Nordhausen were among thousands deported to the Soviet Union after the war to work on advanced rocket and other arms engineering projects. Nordhausen is the birthplace of the famous mathematician Oswald Teichmüller, known for his work on the Teichmüller spaces – which were named after him. It is the site of the Nordhausen University of Applied Sciences, the Franks colonized the area around Nordhausen about 800, many place names here have a Frankish origin, discernible by the suffix -hausen. Nordhausen itself is first mentioned in a 13 May 927 document of King Henry the Fowler and he built a castle here, which is traceable between 910 and 1277 and became a centre of the empire during the 10th century

9.
Combino
–
The Combino is a low-floor tram produced by Siemens Mobility. The first prototype was produced in 1996 at the Duewag works in Düsseldorf, due to its modular design using standardised components, and the resulting reduced costs, the Combino was for a time one of the most successful tram types. They were sold to 12 jurisdictions and a development was sold to two others. In 2007, a new generation of Combinos was sold to Bern and was known as the Combino XL and this was an updated version of the original design and was intended to correct defects in the original design. Subsequently, the model was renamed and is now known as the Avenio M.14 of these were produced in 2011 with 12 going to Erfurt. The Siemens line has been complemented by a new design of trams called the Avenio, unlike the Combino, it does not have suspended sections but rather two axles under each body section. In essence, it is like a train of two axle cars, as of 2014, the Avenio is on order for The Hague and Munich. Around 500 trams went into service in the cities, Twenty-two trams were ordered by Verona, Italy. The length of the trams varies from 19 metres to a world record 54 metres, all versions are designed to have a 300-millimetre floor height and a 10-tonne axle load. It can be built as a one-way or a two-way vehicle, the only city to receive the DuoCombino was Nordhausen, Germany. They usually take 600V DC overhead power and convert this to 400V 3-phase AC power for the regenerative low wear motors via 3 IGBT PWM inverters, on board controls, lighting and air conditioning run at 24V DC. Torsion forces generated in S-curves were much higher than anticipated, leading to cracks around the articulations between the car modules, subsequently, hairline cracks were found in the joints of the aluminium bodies, which could cause the roof to collapse in the case of an accident. The problem was acute in Combino cars that had run more 150,000 km. These flaws were reported in cities that had adopted the Siemens-Combinos, such as Düsseldorf, Freiburg, Augsburg, Erfurt, Hiroshima, Nordhausen, Basel, Potsdam, Bern, Amsterdam. Siemens launched a process of rebuilding the 454 modules affected. Under this process the Combino modules were reinforced to give an expected 30-year life, in 1997, the public transportation authorities of the city of Potsdam were the first to purchase Combino cars. The advantages of its technology were stressed during the introduction. A total of 48 cars were to be bought through 2009, the order from Potsdam was of great importance for advertising the Combino in other cities

Panorama of Karlsruhe, looking south from the palace tower. The Institute of Technology is on the left, the market square in the centre, the Federal Constitutional Court on the right. Note wings of the palace aligning with streets, all radiating out from the centre of town, i.e., the palace tower.