As premetro , short for Unterpflasterbahn tram , underground tram , underground tram or tunnel tram are trams referred, which - by moving underground and unhindered of other traffic - on sections. Originally, these were exclusively tunnels constructed using the paving method , but other construction methods were added later.
In some cities, the subway was the predecessor of the subway or light rail and is also closely related to the express tram . However, the terms are difficult to distinguish from one another. The underground trams usually run classic tram vehicles that are only required to a minimum, e.g. B. with train control systems, have been adapted for operation in tunnels . Low side platforms are therefore used in stations. Route branches are mostly at the same level , due to the consideration of the buildings, narrow curve radii typical for trams are accepted . Signal boxes and route block systems are only available to the extent that is absolutely necessary. The “underground tram” has hardly found its way into everyday language.
The world's first streetcar through a tunnel opened in Boston on September 1, 1897 ; the tunnel has been extended several times, now has eight underground stations and is used by the Green Line . The first underground tram in Germany ran through the Spree tunnel near Berlin , which was completed on December 18, 1899 . The tunnel was closed to tram traffic on February 15, 1932. With the Lindentunnel , opened in 1916 , there was another tram tunnel in the German capital until 1951. On September 3, 1938 in Nuremberg a Unterpflasterbahn route opened since held annually Reichsparteitage with their marches impaired tram traffic too much. Part of Line 7 to Bayernstrasse is still used today . In the rest there is a vehicle warehouse of the Nuremberg Fire Brigade Museum . Since the Nordost depot was closed on February 28, 2001, another part has been used again as a parking facility.
During the 1960s, extensive tunnels were planned in numerous West German cities. Following the general zeitgeist of the " car-friendly city ", trams should be laid in tunnels. Since the high budget in the economic boom was not enough, unfinished (underground) light rail networks and thus incompatible tram networks remained in some cities, especially in the Ruhr area . Even where the conversion was completely successful, for example in Hanover and Stuttgart , the new networks did not reach the density of the old ones.
German-speaking countries (DACH)
In Augsburg , where the tram service has previously operated purely above ground on meter gauge, a tram tunnel including an underground station has been built since 2012 as part of the Augsburg mobility hub project, which tunnels under the main station , the station square and Viktoriastraße. The tunnel running in east-west direction with a length of approx. 410 meters is to go into operation in 2022–2023. To the east, the tunnel is reached by a ramp in Halderstrasse; the western portal is planned on Rosenaustraße at the level of Sebastian-Buchegger-Platz. Part of the project is also an underground turning loop under the shunting tracks of the station.
The first tram tunnel with the Beckhausstraße stop was put into operation in 1971. Light rail railcars could initially only be used on line 3. The completion of the inner city tunnel in April 1991 was the starting point for the Bielefeld Stadtbahn . The six new underground stations that were built in the following years were provided with elevated platforms and were not suitable for the tram vehicles of the time. All old vehicles were therefore replaced by new light rail vehicles. Today the majority of the network is developed as a light rail, only a few sections are still in the street area and are perceived as trams.
All municipal rail lines in Bochum are operated by Bogestra . The U35 line is a fully developed light rail line in standard gauge , which has only four points of contact with private transport, but otherwise runs in a tunnel or on the median of a wide arterial road. The other five lines are classic trams on meter- gauge tracks that cross the Bochum city center underground and thus represent underground trams. In everyday parlance, however, all six lines are sometimes referred to as trams or subways . The platforms of the meter gauge lines on the tunnel sections are each designed as a raised platform, but were high gravels of the tracks practically low platforms. Some of the routes are already being used with low-floor vehicles; In the long term, the high-floor vehicles that are still in existence, all of which are older, will be decommissioned.
- Tram U35: Bochum -Hustadt - Herne Schloss Strünkede
- Tram 302: Bochum-Laer Mitte - Gelsenkirchen -Buer Rathaus
- Tram 306: Bochum main station - Herne-Wanne-Eickel main station
- Tram 308: Bochum Schürbankstraße - Hattingen - Mitte S
- Tram 310: Bochum-Höntrop Church - Witten -Heven Dorf
- Tram 318: Bochum Schürbankstraße - Bochum-Dahlhausen S
In Bonn, trams and light rail vehicles are relatively strictly separated from each other. After the opening of the local transport station in 1979, the regional tram line H (from 1987: 64) was led into the tunnel at the Stadthaus and ended after 600 m at the main station. The three-track Ramersdorf underground station has been used jointly by light rail and tram since 1981 , with both sharing a track to the north. Since line 64 was discontinued in 1994 and the platform was subsequently raised, there are no longer any tram vehicles running at the main train station, there are still short emergency platforms suitable for trams for diversions.
In Dortmund, a 200 m long tram tunnel went into operation in 1967 to undercut the Ruhr Schnellweg in the course of Ardey and Hohen Strasse with the Westfalenhalle underground station, which has since been rebuilt and integrated into the urban railway network (U46). Six high-floor light rail lines and two middle-floor lines, which have more of the character of a tram in the outskirts, run on the three main tunnel routes:
- U41 high-floor tram: Hörde-Dortmund Hbf.-Lünen-Brambauer
- U42 high-floor tram: Hombruch – Reinoldikirche – Grevel
- Middle-floor tram U43: Dorstfeld – Reinoldikirche – Wickede
- Middle-floor tram U44: Marten – Reinoldikirche – Westfalenhütte
- U45 high-floor tram: Dortmund Hbf. – Westfalenhallen
- U46 high-floor tram: Brunnenstrasse – Reinoldikirche – Westfalenhallen
- U47 high-floor tram: Westerfilde – Dortmund Hbf. – Aplerbeck
- U49 high-floor tram: (Hafen) –Dortmund Hbf. – Hacheney
Most of the seven light rail lines operated by Rheinbahn in and around Düsseldorf have their own tracks. Only in the eastern and southern sections of the Eller and Holthausen districts or in the Neuss city area do they use the street space together with individual traffic like the tram lines . In the city center there is a tunnel system with elevated platforms adapted to the high-floor trams. These are also available at several above-ground breakpoints.
Only the tram service between 1981 and 1988 on lines 79, 711 and 718 between Kennedydamm and the Opera House with the underground stations Klever Straße and Nordstraße can be described as an underground tram service. However, light rail vehicles were already being used, which stopped at the fully equipped elevated platforms.
The Wehrhahnlinie , which opened in February 2016, has the character of an underground tram, as it has low-floor platforms. However, it is part of the light rail network and is used with appropriate vehicles.
The former Düsseldorf-Duisburger Kleinbahn now operates as the U 79 light rail line from the Duisburg / Düsseldorf city limits in the south of Duisburg, largely level with the Heerstraße ramp of the inner city tunnel . After several stations (including Duisburg main station ), it continues continuously in a tunnel position in the Ruhr tunnel and ends at Duisburg-Meiderich Süd station .
The Duisburg tram network has now been reduced to two lines. Line 903 uses the same tunnel route as the U 79 between the ramps Heerstraße and Meiderich Südbahnhof, otherwise it only runs partially on its own track to the north to Dinslaken station and to Duisburg-Hüttenheim in the south.
The tram line 901 runs from Duisburg-Obermarxloh over long distances in the same traffic area as private transport. Between the ramps Schwanentor and Mülheimer Strasse, it crosses the Duisburg city center and the main train station in a tunnel. Line 901 travels over tram tracks to the ramp at the depot in Mülheim-Broich and continues through the Mülheim inner city tunnel to Mülheim (Ruhr) main station .
The Ruhrbahn operates the Essen tram and light rail network, which has had underground routes in the city center since 1967.
- Underground U11: Gelsenkirchen Buerer Str. - E-Karnap - Altenessen - Essen Hbf - Rüttenscheid - Messe / Gruga
- Underground U17: Karlsplatz - Essen Hbf - Holsterhausen - Margarethenhöhe
- U-Bahn U18: Berliner Platz - Essen Hbf - Mülheim Rhein-Ruhr-Zentrum - Mülheim an der Ruhr Hbf
- Tram 101: Borbeck - Bergeborbeck - Essen Hbf - Rüttenscheid - Holsterhausen - Helenenstraße
- Tram 103: Dellwig - Borbeck - Altendorf - Essen Town Hall - Essen Hbf / Hollestraße (- Steele Bf)
- Tram 105: Frintrop - Altendorf - Essen Hbf - Bergerhausen - Rellinghausen
- Tram 106: Helenenstraße - Holsterhausen - Rüttenscheid - Essen Hbf - Essen Town Hall - Helenenstraße - Bergeborbeck - Borbeck
- Tram 107: Gelsenkirchen Hbf - Essen-Katernberg - Zollverein - Stoppenberg - Essen City Hall - Hollestraße / Essen Hbf (- Rüttenscheid - Bredeney)
- Tram 108: Bredeney - Rüttenscheid - Essen main station - Essen town hall - Altenessen train station
- Tram 109: Frohnhausen - Altendorf - City Hall Essen - Huttrop - Steele Bf
Through part of the tunnel sections for a time drove long the duo buses as guided bus . Because of the existing central platforms of the tunnel stations, the vehicles were given special doors on the left side.
Frankfurt am Main
For more than 30 years , the U5 line ran in Frankfurt am Main in the B tunnel of the Frankfurt U-Bahn and therefore had a U in front of the line number. It still shares the tracks with private traffic between Nordend and Eckenheim . The vehicles used were tram-compatible light rail vehicles of the Ptb type with widened doors and folding steps. Since October 2016, after the construction of elevated platforms, as in the rest of the Frankfurt subway network, type U5 cars have been used. This underground tram was a holdover from the time it was built in the 1960s. When planning and executing the first underground lines, it was planned from the outset so that underground and tram vehicles could use the same tracks on sections of the route. The networks were only gradually separated from each other by the construction of high and low-floor platforms.
In Gelsenkirchen, line 301 runs about 5 km underground from the main train station to the Zoom Erlebniswelt . The train runs above ground from the Zoom Erlebniswelt to the terminus at Essener Straße . The lines 107 and 302 also use the tunnel section from Gelsenkirchen main station to the music theater or to Rheinelbestr. (three or four stations). Originally, a light rail network was also planned in Gelsenkirchen, but due to unfavorable circumstances (slow subsidence of the ground due to mining ) a completely new system for tunneling had to be designed for Gelsenkirchen. This increased the costs to double the normal price (around 40 million euros per kilometer).
At the Heinrich-König-Platz stop (formerly Neumarkt ) the remains of the elevated platform can still be clearly seen; only parts of the elevated platform were lowered there. At the Gelsenkirchen Hauptbahnhof stop , on the other hand, the elevated platforms were almost completely demolished (except for small platforms at the exits), so that there is a usable low platform 120 m long. At the other tunnel stops, because the ceiling height allowed it, the tracks were graveled higher.
- Tram 107: Essen Hbf / Hollestraße - Gelsenkirchen Hbf
- Tram 301: Gelsenkirchen Hbf - Horst
- Tram 302: Gelsenkirchen-Buer Rathaus - Bochum-Laer Mitte
The Hanover light rail system consists of a tunnel system with subsequent above-ground routes in the street area. Two lines from the inner city are still running as pure trams. All lines are operated with light rail vehicles.
In the preliminary operation for the light rail, older tram cars for underground tram operation were converted and equipped with folding steps . These cars should be able to stop both at the elevated platforms of the light rail (or subway ) and in the street area at tram stops. Due to construction delays and the use of new trams that were already available, the converted trams were never used in the tunnel.
In Karlsruhe, where the tram and light rail operations to the surrounding area based on the Karlsruhe model have so far been above ground, the "combined solution " has been built since 2010 , an east-west light rail tunnel under Kaiserstraße including the south branch under Karl-Friedrich- and Ettlinger Straße and a car tunnel under the Kriegsstrasse including an above-ground tram route. A tram-free pedestrian zone is to be reached by the end of 2020.
From 1968 to 2005 there was a 200 m long tram tunnel with an underground stop at the main station.
This underground tram was abandoned due to the redesign of the pure tram operation, which had previously been separate from regional traffic, and was replaced by a parallel above-ground route in Rudolf-Schwander-Straße. The city's new Regiotram concept connects trams and regional trains . For this purpose, a new tunnel was built at the main train station in 2006 with a stop in a trough position parallel to the railroad tracks, which thus takes on the function of a tram tunnel . This tunnel uses the southern tunnel ramp of the former tram tunnel.
The tram routes in downtown Cologne , which were not rebuilt during / after the war , were replaced by an underground tram tunnel that was opened in 1968 and has branches at the same level and tight curve radii. As a result, the network was gradually brought up to light rail standard through further tunnels with a higher standard, separate railways in the street area with public transport priority and individual new lines.
The Cologne Stadtbahn network, which today only comprises twelve lines, has been divided into a high-floor and a low-floor section since the mid-1990s . With a few exceptions, all of the lines now have their own full length of their own railway bodies, tunnels or elevated railway lines.
Ludwigshafen / Mannheim
There are also some underground tram routes in Ludwigshafen am Rhein and Mannheim . These extend in Ludwigshafen on the northern edge of the city center from the town hall over Danziger Platz to the main station and in Mannheim also on the northern edge of the city center from Rheinstrasse along the Luisenring to the MVV high-rise .
The first sections were opened in 1969, but expansion plans for subway tram routes that went beyond the existing sections were no longer implemented. In December 2008, the regular service from the Ludwigshafen town hall to the main train station was suspended due to a lack of demand. Most recently, the route was only served during rush hour. The underground train station integrated into the Rathaus-Center remains in use.
In the southern part of Nuremberg there is a short tram tunnel on tram line 7 between the Tristanstraße stop and the Bayernstraße terminus, which dates back to the Nazi era. Due to the risk of collapse, however, it has no longer been allowed to use people since December 12, 2010, so that although the Bayernstraße loop and the tunnel can be used, passengers have to get off at the Tristanstraße station. The future of the tunnel is uncertain because of the high renovation costs and a possible extension of the tram into the new development area “Brunecker Straße”, which would make the loop on Bayernstraße superfluous.
In April 2003, as part of the expansion of the tram network, a 338 m long tunnel was put into operation, which includes the underground station “Hauptbahnhof”.
The Schwab Tunnel under the Hasenberg between Stuttgart-West and Stuttgart-Heslach is an ancestor of all tram tunnels, perhaps even the second oldest in Germany (after the Spreetunnel Treptow-Stralau opened in Berlin in 1899), with a length of 125 m and width of 10.5 m, completed in 1896 and shared by trams from 1902 to 1972. Another combined tram and tram tunnel went into operation at the end of 1968 under the newly built Kleiner Schloßplatz between Schloßstraße and Schloßplatz .
The real underground tram era began in Stuttgart with the two-story Charlottenplatz underground station, which was completed in 1966/1967, and four short connecting tunnels, with ramps in Charlottenstraße and Planie (1966) and in Konrad-Adenauer-Straße (then Neckarstrasse ) and Holzstrasse (1967). This was followed in 1971 by the tunnel from Charlottenplatz via the intersection-free Gleisdreieck Torstraße to the ramp in Böblinger Straße (via the Rathaus , Österreichischer Platz and Marienplatz stations ) and in 1972 the extension from Charlottenplatz to the ramp on Stöckach with the Staatsgalerie and Neckartor stations , with a branch tunnel from Central station ( Schillerstraße ramp ) to the three-track Staatsgalerie station , and from the Torstraße triangle to the ramp in Eberhardstraße ( Wilhelmsbau stop ).
These and all other tunnels were dimensioned as an advance payment for possible later system changes so that they could not only have 2.30 m wide trams, but also 2.65 m wide light rail vehicles (such as the large-profile cars of the Berlin U-Bahn and the later Stuttgart light rail vehicles ) and could even accommodate 2.90 m wide vehicles (like the later Munich and Nuremberg subways), which could then no longer run outside the tunnels in the street space. In 1976 the four-track underground station at Arnulf-Klett-Platz / Hauptbahnhof followed with a connection in Schillerstraße to the route towards the State Gallery , with a ramp in lower Königstraße , a tunnel into Schloßstraße ( Berliner Platz / Liederhalle ) with the Universität train station (today Börsenplatz ) , as well as another tunnel in Heilbronner Straße with the Türlenstraße train station (today the city library ). In 1983 the underground Wilhelmsbau / Stadtmitte station and a tunnel up to the ramp in front of the Berliner Platz / Hohe Strasse stop in Fritz-Elsas-Strasse followed, extending the line from the Torstrasse triangle .
After experience had been gained with the new light rail from 1982 to 1983 on a trial basis and from 1985 in regular service on the above-ground route (U3) on the Filder plain , in April 1986 ( Vaihingen - Charlottenplatz - Fellbach , U1) and July ( Heslach - Hbf. - Mühlhausen , U14) the first trams are also in operation in tunnel sections. This started a 21-year mixed operation between meter-gauge subway trams and standard-gauge subway-like light rail vehicles. For this purpose, three-rail tracks were gradually laid and elevated and low-level platforms that were divided in length were set up in the stations. And more tunnels were built: in 1990 from the Bopser to the Neue Weinsteige , also in 1990 the Pragsattel station, which is open to the top, with access ramps from Pragstrasse and Heilbronner Strasse and two connecting tunnels to the outer Heilbronner Strasse and through Siemensstrasse via Maybachstrasse station to the ramp tunnel road , and later in the Feuerbach tunnel from the station Feuerbach on the open at the top station Wilhelm-Geiger-Platz to the open-sided station Feuerbach hospital (now Föhrich ). In 1992 the Weilimdorf tunnel followed on this route with the Löwenmarkt train station open at the top and the Rastatter Straße ramp stop .
The tunnel to what was then the Killesberg exhibition center, opened in 1993, was only served by light rail vehicles from the start, as was the tunnel to Botnang between Herderplatz and Lindpaintnerstraße in 1994 , the tunnels between Gerlingen Siedlung and Gerlingen terminus (1997) and between Schlotterbeckstraße and Karl-Benz-Platz in Untertürkheim (1998), the Waldau tunnel between Bopser and Ruhbank with the Waldau train station (1998) and then the two tunnels in Sillenbuch (1999) and Ostfildern- Ruit (2000), the tunnel under the main cemetery to Neugereut (2005) and later am Fasanenhof (2010).
On December 8, 2007, the last tram line (line 15 to Stammheim ) was discontinued in order to expand it into a light rail with the Zuffenhausen tunnel opened in 2011 ( Zuffenhausen Town Hall - Kirchtalstraße - ramp stop Salzwiesenstraße ). This ended the history of the Stuttgart underground tram. Three-rail track and underground platforms will only be preserved to a limited extent for the museum lines of the Stuttgart Tram World.
Similar to Linz , an underground tram line was built in Graz in the area of the main train station. Before the renovation work began, only tram lines 3 and 6 went directly to the main train station, lines 1 and 7 passed it about 200 meters south of the train station. Since the completion of the new route with an underground station at the main train station on November 26, 2012, it has been served by lines 1, 3, 6 and 7 and, since 2020, by lines 1, 4, 6 and 7.
Originally only line 3 of the tram led to the main train station in Linz , lines 1 and 2 passed it around 400 meters. On August 31, 2004, an underground tram line was opened, which has two underground stations “Hauptbahnhof” and “Unionkreuzung” and the semi-underground station “Herz-Jesu-Kirche”. Since the opening of this route, all tram lines have served the Hauptbahnhof station. There is an underground turning loop north and south of the underground station Hauptbahnhof.
Between 2009 and 2011, a junction and a further underground tunnel stretching 1.3 kilometers in the direction of Leonding were built in the area of the southern Wendeschleife, which has no underground stations. Since the opening of this route in August 2011, line 3 has been running on this route in the direction of Leonding.
In Vienna , the first underground route of Wiener Linien was opened in 1959 at Südtiroler Platz: a short underpass of the square in the course of the belt ; the stop (it bears the name Hauptbahnhof today ) is connected to the also underground S-Bahn station, now called Wien Hauptbahnhof (Südtiroler Platz) .
By 1969, following this underpass, the tracks on the southern belt up to Eichenstrasse and a junction through Kliebergasse into Wiedner Hauptstrasse were lowered. The tunnel, which now has six underground stops, is now used by lines 1, 6, 18, 62 and the Badner Bahn . In 1961, the Schottentor loop system on the Ringstrasse was put into operation: The above-ground loop is used by lines 43 and 44, the one below in an open-topped rondeau by lines 37, 38, 40, 41 and 42. That has been the case since 1980 at the time, after the mayor, so called " Jonasreindl " combined with the Schottentor underground station on the U2 line.
In 1966, the defunct by the three today tramlines E was 2 , G 2 and H 2 busy two-line deep down between Secession and Regional Court. This officially Ustraba (= Unterpflasterstraßenbahn), popularly called U-Strab, had four stops. In 1980 it was converted to the U2 subway line (Karlsplatz – Schottenring), the station names were partially changed and the Lerchenfelder Straße station was closed in 2003 as part of the extension of the U2 due to insufficient distance from the Volkstheater subway station .
Independently of this, classic tram cars were running on tunnel sections on Vienna's electric light rail as early as 1925.
The Zurich tram runs between the Milchbuck and Schwamendingerplatz stops in the 2.5 kilometer-long Milchbuck – Schwamendingen tram tunnel with three underground stations. This was created during the construction of the motorway that leads from the north into the city and is a remnant of the Zurich subway plans , the implementation of which failed on May 20, 1973 in a cantonal referendum because of the high costs and questionable benefits. Since the tunnel stations have central platforms , the trams change to the left in the area of the tunnel portals because they only have doors on the right side.
Rest of Europe
In 2005 the network looked like this:
Here is a list of the lines that use the tunnel: (Stops in the tunnel are in bold)
- 2 Hoboken - Plantin - Fredrick van Eden - Linkeroever
- 3 Merksem - Sport - Fredrick van Eden - Zwijndrecht
- 5 Wim Saerensplein - Schijnpoort - Fredrick van Eden - Linkeroever
- 6 Luchtbal - Sport - Plantin - Olympiad
- 15 Mortsel - Plantin - Fredrick van Eden - Linkeroever
As a predecessor of some metro lines is evident in Brussels the Premetro . Today trams still run underground between Gare du Nord / Noordstation and Albert with additional ramps at / at the Gare du Midi / Zuidstation and in Lemonnier as well as on the Grande Ceinture between Boileau and Diamant and as an underground loop in Montgomery and as a stop in Simonis. The following tram lines run partly underground: 3, 4, 7, 19, 25, 39, 44, 51, 55, 81 and 82 as well as the evening lines 31, 32 and 33.
As part of the modernization of the meter-gauge tram and the opening of the subway of Lille were in 1983 several short underground sections and stops as Gare de Lille Europe and Gare de Lille-Flandres , where there are also connections for the metro, put into operation.
Already in 1893 was for the tramway of Marseille , a 600 meter long tunnel with an underground station Noailles built to allow better access to the city center. Today Noailles is an important transfer point between the tram and the Marseille metro .
In Rome , a tram tunnel was built and partially completed, but never put into operation.
The M51 line of the Amsterdam subway in Amsterdam ran between 1990 and 2019 from Amsterdam Central Station to Amsterdam South Station as a normal metro , then partly together with the Amsterdam tram to Amstelveen Westwijk. Today, however, it no longer serves the section to Westwijk and is operated as a subway, while the former tram section is being expanded as an independent, low-floor line. The reason was that, on the one hand, a motorway near the Südbahnhof had to be widened, so that there was no space for connecting the underground to the tram route, and disruptions from road traffic on this section always affected the otherwise independent underground -Net off.
In the course of the introduction of high-speed tram lines in the Kraków network, a tunnel section was opened in 2008, which connects the underground stations “Politechnika” and “Dworzec Główny Tunel” (main train station).
In 1998, as part of an extension of line 8, the Brno tram opened an underground stop in the Brno-Líšeň district (Brno-Lösch).
There are four underground tram stops in Toronto, three of which are integrated into Toronto subway stations . These are the Union (509 and 510) and Spadina (510 and 510K) stations, both of which were supplemented by an underground turning loop in 1990, as well as the St. Clair West station (512), which has also served trams since its opening in 1978 serves. The Queens Quay tunnel station (509 and 510) south of Union Station , which went into operation in 1990, is reserved exclusively for tram traffic .
In Boston , the Massachusetts Bay Transportation Authority (MBTA) operates three subway lines as well as the Green Line tram , which is divided into branches B , C , D and E - Green Line A was discontinued in 1969 - which runs within the city center still uses the world's first tram tunnel, but is laid out as a surface line in the outskirts . The Green Line emerged from the Tremont Street Subway and connects Boston city center with neighboring districts and surrounding communities.
The city in New Jersey has had a stretch of tunnels that has been used by streetcars and light rail vehicles since 1935. The first section ran between the stations of Broad Street (now Military Park) and Warren Street (now Warren Street / NJIT) underground (with the intermediate station Washington Street), in 1937 the tram tunnel was extended to the south in the course of the completion of Newark Pennsylvania Station To enable connection to the long-distance trains. Today, the vehicles of the Newark Light Rail light rail service all four underground stations.
A total of five tram lines in Philadelphia, which open up some suburbs and suburbs west of the Schuylkill, start in the city center in an underground turning loop that runs around the city hall. From there, the main line runs together with the Market – Frankford Line of the subway in a four-track tunnel below Market Street to the west to past 30th Street Station.
The Buffalo Metro Rail, which opened in 1984, runs underground for a large part. In May 1985, the six-station tunnel section between Allen / Medical Campus and Amherst Street was opened to traffic, and in November 1986 it was extended to the University station with the LaSalle intermediate station. The underground part of the light rail line now has a length of 8.4 km.
A total of 115 kilometers long network in San Francisco is served by six lines, which all run through a central tunnel. This tunnel has nine stations and consists of two sections. The first, called the Twin Peaks Tunnel, was opened in 1918 and is crossed by four of the six lines. When it opened, it was one of the longest tram tunnels in the world. The second part is the Market Street Subway, a joint structure with the BART , through which all lines pass. This tunnel was put into operation for BART in 1973. 1980 the level above for the Muni Metro. Another tunnel, called the Central Subway, which crosses Market Street, is currently under construction.
Seattle has had a public transport tunnel system since 1990, which was built in three stages. In 1990 the 2.1 km long Downtown Seattle Tunnel was opened, in which initially only operated by bus lines of the King County Metro and Sound Transit Express companies. From 2009 on, the Seattle (Central Link Light Rail) trains also ran through the tunnel, which connects the four underground stations Westlake, University Street, Pioneer Square and International District / Chinatown. In the further course of the line to the south, the Beacon Hill station was another tunnel-built station. In March 2016, the 5.07 km long University Link tunnel was finally opened to regular traffic, which connects to the north end of the Downtown Seattle Transit Tunnel and leads to the campus of the University of Washington. Unlike the Downtown Seattle Transit Tunnel, the two underground stations, Capitol Hill and University of Washington, are only served by Seattle light rail trains. There are also plans to extend the tunnel to Northgate. While the Northgate terminus is to be built above ground, two more underground stations are planned for the U District and Roosevelt stops. The first construction work began in 2012 and completion is planned for 2021. For the "East Link Extension" extension of the line network to the east with a terminus in Redmond, which is to be implemented by 2023, an underground extension from the Downtown Seattle Transit Tunnel and three further tunnel sections are planned. However, all stations on this new line will be located above ground.
- Hans-Joachim Pohl: The Lindentunnel . In: Verkehrsgeschichtliche Blätter . Issue 7, 1980, pp. 134-150 .
- Project Augsburg City , accessed on September 25, 2013
- Cessation of passenger service in the tunnel on December 12, 2010 in nordbayern.de from December 11, 2010, accessed on December 15, 2010.
- https://eisenbahn-tunnelportale.de/lb/inhalt/tunnelportale/h6101.html Data and pictures from the main station tunnel in Rostock
- Alfred Brunold, Traffic Planning and Urban Development, Stuttgart Studies Volume 4, the urban development of the Stuttgart railway site - a case study. First edition Stuttgart 1992, Silberburg-Verlag Titus Häussermann. ISBN 3-87407-130-8 . As pdf:  , in particular pages 98, 163, 174 to 178, 209 to 210, 220 to 221, 224 and 242, accessed on May 30, 2019
- From 2011 the tram will go to the Harter Plateau. Upper Austria. News, March 24, 2009, accessed February 2, 2020 .
- https://www.nycsubway.org/wiki/Newark,_New_Jersey_Light_Rail/City_Subway Newark, New Jersey Light Rail / City Subway
- http://metro.nfta.com/About/History.aspx History of Metro
- https://systemexpansion.soundtransit.org/?_ga=2.152820476.477912368.1534190082-1016232879.1534190082 System expansion interactive map