Semi-metro

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Muni Metro Forest Hill station M Ocean View train at Forest Hill station, November 2018.jpg
Muni Metro Forest Hill station
Sound Transit Airport station Coming in on the priority track (4283902657).jpg
Sound Transit Airport station

Semi-metro is a type of light rail in which trams or light rail trains run partly on a conflict-free track, usually in the city centre, and partially on tracks with level crossings with other traffic. [1] [2] To achieve conflict-free sections, the tracks are in tunnels, on viaducts, or occasionally in trenches. [3] [4] Semi-metro can refer to the whole of a network with sections in tunnels/viaducts or only refer to the sections of that network with tunnels/viaducts. This type of transit is also referred to by various other terms, including subway–surface light rail [5] [6] [7] [8] or subway–surface system. [9] : 517 

Contents

Dedicated stretches of track are designed to function similarly to regular metro or rapid transit lines. [10] [11] One key difference from metro (rapid transit) is that a metro line has an entirely conflict-free track, often completely grade separated, whereas semi-metro has lines with only one or a few sections in tunnels and on viaducts. [12] [13]

Semi-metro systems run with tram vehicles, as they are usually developed from an existing tram network. [14] [15] [16] Semi-metro routes are operated either with regular trams (with or without low floor) or with specially developed tramcars (light rail vehicles), such as the Stadtbahn-car 'type B'. [17] : 55  Most semi-metro systems (including in the United States), [18] are operated with larger and heavier vehicles than those on streetcar systems. [12]

Terminology

Semi-metro type transit falls under the family of light rail types, [2] [12] [19] [20] [21] [22] which includes many kinds of modern transport derived from tram technology. Semi-metro is in itself a container concept in which premetro and Stadtbahn fall. [17] : 9,10  In 1962 American transport planner Quinby wrote about a new type of transit, departing from the old "street railway" and reshaping it to form the "limited tramway". Key differences that he mentioned were the development of new, larger rolling stock and the use of grade-separated sections in core urban areas. [23]

More archaic terms that have been used are: subway–surface trolly/streetcar, [24] [25] tram subway, [26] or trolley subway. [27] An alternative predominantly used in former Soviet countries is metrotram [28] [29] or in the U.S. occasionally the term Subway LRT [30] or hybrid streetcar/light rail line. [31]

Features

Semi-metro systems sit between rapid transit (with higher investments and a higher capacity and speed) and buses and trams in city streets (with lower investments and a lower capacity and speed). Such systems combine advantages of greater speed (like rapid transit) and better coverage in suburban areas (like buses and trams). [32] Although cheaper than a metro line, the construction of infrastructure for semi-metro routes is often still too expensive. [33] Therefore some sections of the line are sometimes constructed later than others, or not at all. [34] The direct contact with the existing tram network is an advantage compared to constructing a separate light metro line. [35] [36] Often several tram branches at grade are needed in order to make fully use of the high capacity tunnels. [37] [9] : 518 

Right-of-way category

Outbound train on South Huntington Avenue (2), September 2022.JPG
Inbound train at Allston Street station (2), August 2018.JPG
Prudential Eastbound MBTA Green Line Platform, November 2024.jpg
Semi-metro systems combine tram-like or separated tracks (category C/B, left/middle) with independent metro-like infrastructure (category A, right)
Elevated section in Cologne. KVB5208 Neusser Strasse Gurtel.JPG
Elevated section in Cologne.

A rail transit system is categorised first by its main right-of-way category, and secondly by other parameters like power supply and operating speed. [17] : 6  [38] Three major right-of-way categories can be distinguished, labelled A, B and C by Vuchic:

Typically, a tram/streetcar line has mostly category C, a light rail line has mostly category B and a semi-metro line has some of category A (combined with category B and sometimes C). [38] [39]

Alternatively, the Transportation Research Board terms the independent right-of-way as grade separated: including "facilities located at grade, where modes cross over or under the facility". The reserved right-of-way is termed exclusive, and a subtype is distinguished: semi-exclusive, which means an environment with reduced other modes of traffic. [40] Whenever light rail vehicles operate only using category A, it is defined as "light rail rapid transit" (LRRT) and is part of the greater light metro class. [41]

Tremont Street subway in 1897 Huntington Avenue streetcar at Park Street station, 1897.jpg
Tremont Street subway in 1897

History

An early example with semi-metro characteristics was the Murray Hill Tunnel in New York, which was completed in 1850, [42] with an underground streetcar station that opened in 1870. [43] Streetcars continued to run until 1935, and the tunnel was reopened as a road tunnel in 1937 after reconstruction. The first city in Europe to carry a portion of a streetcar line through the city center in a tunnel was Marseille, France, in 1893, with its Noailles subterranean station (see Marseille tramway). It was initially operated by horse-drawn wagons. A prominent example is the Tremont Street subway (1897) in Boston, [44] [45] [46] today part of the MBTA Green Line. After a local Washington D.C. newspaper had already presented plans for a rapid transit network in 1909, the government drew up a comprehensive plan in 1944. It included tram tunnels similar to those built in Boston. The plans were not implemented after the war. [47]

Kingsway tramway subway portal in 1933 Kingsway Tram Tunnel 1933.jpg
Kingsway tramway subway portal in 1933

The Kingsway tramway subway is a cut-and-cover tunnel in central London, built by the London County Council. The subway opened in 1906 and closed in 1952. The southern end was adapted as a traffic underpass in 1964. The separate northern section was listed at Grade II by Historic England in 1998. [48] After study trips to Sweden and Boston, W. Vane Morland introduced the semi-metro concept in 1944 in Leeds, which still had a tram network at the time. Fast tram lines to the south and east were built, and plans were made to connect these to tram tunnels in the city center. In 1948, Eric Fitzpayne proposed the same in Glasgow, and a fast tram line to Blairdardie was completed in 1949. Both cities were unable to complete their plans and even lost their tram networks due to a lack of political will. [49] In Glasgow, the idea for a semi-metro resurfaced in 1973, this time as an extension of the city's small rapid transit system. The plan proposed to create a network that connected the existing metro ring with old Light Railway lines. The inspiration came from similar systems in Europe and North America that were being upgraded. [50] Brussels, Cologne and Frankfurt pioneered in Europe with longer tunnels with multiple stations starting in the 1950s, reinventing the idea of the Tremont Street subway. [46]

Subtypes

STIB/MIVB Simonis station Tramlijn 9 Brussel 2018 2.jpg
STIB/MIVB Simonis station
ustra Marienstrasse station Stadtbahn Hannover 11 2570 Marienstrasse 2006280748.jpg
üstra Marienstraße station

Besides regular semi-metro networks, two subtypes exist. Both terms refer to tram networks where tram vehicles use viaducts and/or run through tunnels under city centres, but with key differences:

Premetro

Premetro is largely equal to semi-metro: a type of public transport in which trams run partly grade separated, by using tunnels and/or viaducts. However, there is one clear distinguishing factor: premetro uses infrastructure that has been explicitly constructed with the ambition to transfer to use metro trains in the future. [9] : 521  [17] : 9  [51] [52] It is usually also developed from an existing classic tram network. One prominent example is the premetro in Brussels, where several premetro lines have been or will be converted into full heavy rail metro lines.

U-Stadtbahn

The U-Stadtbahn is also an intermediate transportation form between metro and tram. It has originated in Germany, adapting the existing tram networks. Here specially developed trams run underground through tunnels in central urban areas. [17] : 10  [53] [54] Stadtbahn lines can be subdivided by looking at the types of rolling stock.

Examples

In the United States, the most prominent examples that can be categorised as semi-metro are the San Francisco Muni Metro [20] and the Green Line in Boston. [55] [17] : 9  The Buffalo Metro Rail, Seattle's Link light rail, [56] the light rail lines in Cleveland [57] and the MetroLink in St. Louis [58] are also considered semi-metro. A clear example in Canada is the Edmonton LRT (Capital and Metro lines). [17] : 77  In the United Kingdom, the Tyne and Wear Metro would be, by this definition, a semi-metro system due to eight level crossings. [59]

Notable examples in Germany are the Hanover Stadtbahn, [12] the Stuttgart Stadtbahn [35] the Essen, Bonn and Cologne Stadtbahns [60] plus the system in Frankfurt. [17] : 9  [61] : 36  Over several decades a semi-metro system was constructed in the Dutch city of The Hague. [62] [63] [64] The Brussels premetro is sometimes also referred to as semi-metro, [61] : 36  as the term was originally coined there; this was before switching to the concept of pre-metro. Other networks in Belgium exist in Antwerp and Charleroi. [65]

In France the networks of Rouen, Strasbourg and Nice are the most prominent ones. [66] In Central Europe, the cities Brno, Linz and Graz provide underground sections, just like Vienna where trams also use premetro infrastructure. More recent examples that could be categorised as semi-metro are the Madrid Metro Ligero, [67] the Málaga Metro and Alicante Metropolitan-Tram in Spain and the Porto Metro in Portugal. [68]

In the 21st century new light rail systems have been built that include grade-separated sections of infrastructure. These include the T4 of the Istanbul tramnetwork, the Lusail Tram in Doha and the Red line in Tel Aviv in the Middle-East. In the east of Asia examples include the Green Mountain line in Danhai New Town, Line 3 in Changchun and the Optics Valley tram in Wuhan.

References

  1. ↑ International Study Week in Traffic Engineering: Reports pt.2 (in French). O.T.A. / Northwestern University. 1972. p. 44. Retrieved 3 September 2024.
  2. 1 2 Zaborowski, dr Łukasz (2018). Tramwaj dla polskich miast (in Polish). Instytut Sobieskiego. p. 32, 33. Retrieved 3 September 2024. Do lekkiej kolei zaliczymy także systemy pośrednie między metrem a tramwajem. Bezkolizyjność trasy oraz kolejowy system sterowania w połączeniu z taborem tramwajowym to semi-metro. System taki może działać jako semi-metro w obszarze śródmiejskim, a w dzielnicach zewnętrznych jako szybki tramwaj. — Light rail also includes intermediate systems between the metro and the tram. The collision-free route and the railway control system combined with the tram rolling stock are called semi-metro. Such a system can operate as a semi-metro in the city center, and in the outer districts as a rapid tram.
  3. ↑ Weigelt, Horst; Weiss, Helmut H.; Götz, Rainer E. (1977). City Traffic: A Systems Digest. Van Nostrand Reinhold. p. 44. ISBN   978-0-442-29259-1.
  4. ↑ Intersociety Conference on Transportation (1976). Proceedings: fourth annual Intersociety Conference on Transportation. American Society of Mechanical Engineers.
  5. ↑ Boske, Leigh B. (1998). Multimodal/intermodal Transportation in the United States, Western Europe and Latin America: Governmental Policies, Plans and Programs. LBJ School, UT Austin. p. 172. ISBN   978-0-89940-743-2 . Retrieved 9 April 2025.
  6. ↑ Canadian Embassy. (1982). Canada Today: Canada D'aujourd'hui, Volumes 13-15 . Retrieved 16 February 2023. light rail subway/surface line
  7. ↑ John W., Schumann. "What's New in North American Light Rail Transit Projects?". TRB Special Report. 221 (Light Rail Transit: New System Successes at Affordable Prices): 31. Retrieved 24 July 2024. By the late 1960s, this costly proposal had foundered, and the Muni Metro concept emerged: use subway-surface rail cars (the term LRV was not yet invented) to provide no-transfer service directly to the CBD on the existing five streetcar lines and through the new subway.
  8. ↑ Urban Mass Transportation Abstracts. Urban Mass Transportation Administration. 1972. Retrieved 9 April 2025.
  9. 1 2 3 "The Rapid Tramway: A Feasible Solution to the Urban Transportation Problem". Traffic Quarterly. 24 (4). 1970. ISSN   0041-0713 . Retrieved 7 April 2024.
  10. ↑ Organisation for Economic Co-operation and Development. (1973). The Automobile and the Environment . Retrieved 9 February 2023. descending into tunnels in the style of conventional underground mass transit
  11. ↑ Norley, Kym (2010). Light rail: The semi-metro concept. p. 4. Semi-metro: Light rail on reserved right of way over congested parts of line typically in tunnel or viaduct for grade separation designed to Metro standards, with priority surface light rail in other sections
  12. 1 2 3 4 Cappelli, Agostino; Nocera, Silvio; Libardo, Alessandra (2013). Environment, land use and transportation systems: selected papers. p. 42. Retrieved 22 March 2024. Rather soon attention was given to Light Rapid Transit modes such as pre-metro and semi-metro (Hannover) employing heavy trams instead of light trains to run on open-air independent or semi-independent tracks, and just and just seldom using short bypass tunnels or fly-evers to skip congestion in central areas.
  13. ↑ Orski, C.K. (1973). "New Transportation Service Concepts". Proceedings of the International Conference on Transportation Research: 407. Retrieved 9 February 2023.
  14. ↑ "Seventeenth Annual Report and Resolutions of the Council of Ministers". Annual Report (17). OECD: 40. 31 January 1971.
  15. ↑ Implementation of Transportation Controls: Hearing, Ninety-third congress. Washington, D.C. 1974. p. 492. Retrieved 17 January 2023. In essence, a semi-metro consists of light rail cars operating on exclusive tracks, generally on the surface but descending into tunnels in the style of conventional underground mass transit in city centres{{cite book}}: CS1 maint: location missing publisher (link)
  16. ↑ U.S., Transportation Research Board. "Transportation Research Board Special Report 179". National Academy of Sciences. Retrieved 17 January 2023.
  17. 1 2 3 4 5 6 7 8 De Leuw, Cather & Company (1976). Light Rail Transit: A State of the Art Review . Retrieved 8 February 2023.
  18. ↑ Sharing of Rail Transit Infrastructure by Streetcars and Larger Light Rail Vehicles: Design and Operational Issues. Washington, DC: American Public Transportation Association. 2006. ISBN   978-1-931594-23-3 . Retrieved 20 November 2024.
  19. ↑ "11 Glossary and symbols". Transit Capacity and Quality of Service Manual. Transportation Research Board. 2013. p. 53. ISBN   978-0-309-28344-1.
  20. 1 2 George E. Gray, Lester A. Hoel (1992). Public transportation (2nd ed.). Englewood Cliffs, N.J.: Prentice Hall. pp. 131, 739. ISBN   9780137263813 . Retrieved 8 February 2023.
  21. ↑ Rimmer, P J (1 December 1987). Research Policy and Review 20. The World Bank's Urban Transport Policy: Authorised Version, Revised Version and the Apocrypha. p. 1575. Retrieved 20 August 2025. Light rail transit: Low-cost trams to high-cost semi-metro on exclusive track
  22. ↑ Armstrong-Wright, Alan (1986). "Urban Transport in LDCs". Finance & Development. 23 (3): 48. Light rail transit, ranging from low-cost trams operating along public streets to high-cost semi-metro rail systems on exclusive tracks.
  23. ↑ Quinby, H.D. (1962). "Major Urban Corridor Facilities: A New Concept". Traffic quarterly: 248–249. Retrieved 9 April 2025.
  24. ↑ Transportation Research Board (2003). 9th National Light Rail Transit Conference. p. 29. Archived from the original on 16 February 2023. Retrieved 16 February 2023. By this time, there was considerable interest in reconfiguring the U.S. subway-surface streetcar systems to resemble northern European practice, and there was increasing recognition that modern tramways might be appropriate for urban regions that long since had given up streetcar operation.
  25. ↑ Thompson, G. L. Defining an Alternative Future: Birth of the Light Rail Movement in North America. pp. 28–29. Retrieved 9 April 2025.
  26. ↑ "The tram subways of Philadelphia - A history and a forward look". Modern Tramway and Light Railway Review. 26 (306). Ian Allan; Light Railway Transport League: 205. June 1963.
  27. ↑ Middleton, William D. (2003). Metropolitan Railways: Rapid Transit in America. Indiana University Press. pp. 145–147. ISBN   978-0-253-34179-2.
  28. ↑ "метротрам". Словари и энциклопедии на Академике (in Russian). Retrieved 9 April 2025.
  29. ↑ "Метротрам как высшая стадия развития трамвая. Почти как метрополитен, но в три раза дешевле". Zen (in Russian). Retrieved 9 April 2025.
  30. ↑ "A Vision for Rapid Transit in San Francisco". archives.sfmta.com. SFMTA. Retrieved 9 April 2025.
  31. ↑ NACTO. "Streetcar and Light Rail Characteristics". National Association of City Transportation Officials. Retrieved 16 February 2023.
  32. ↑ "Another Alternative: The Case for Light Rail, Part 2". Transit Journal. 1 (3). American Public Transit Association.: 56 August 1975.
  33. ↑ Duin, Leen (2009). The Urban Project: Architectural Intervention in Urban Areas. IOS Press. p. 80. ISBN   978-1-58603-999-8 . Retrieved 31 March 2025.
  34. ↑ A Report on the ... Conference on Mass Transportation. United Transportation Union. 1966. p. 53. Retrieved 18 March 2025.
  35. 1 2 White, Peter (2016). "Light rapid transit (LRT) (also known as light rail)". Public transport: its planning, management and operation (Edition 6 ed.). New York. ISBN   9781317383178. In other cases, a tramway may be upgraded by extensive construction of city-centre tunnels, and some stations at which all tickets are sold prior to boarding the vehicle ('semi-metro'), for example in Stuttgart. An advantage of such systems is that trams can be diverted into relatively short sections of tunnel as they are built, rather than waiting for a major portion ofthe system to be completed before operations can commence.{{cite book}}: CS1 maint: location missing publisher (link)
  36. ↑ van Lith, Joske. "Geluidloos zoeven door Rennes". Verkeerskunde (in Dutch). Retrieved 2 February 2023.
  37. ↑ ECMT Round Tables (1975). Economic Problems of Traffic Peaks. Organisation for Economic Co-operation and Development. p. 39. Retrieved 31 March 2025.
  38. 1 2 Vuchic, Vukan R. (1986). Trends in the Development of Urban Passenger Transport Systems and Vehicles. Fisita. p. 31-32.
  39. ↑ Vuchic, Vukan R. (14 January 2002). Urban Public Transportation Systems. University of Pennsylvania. pp. 4, 5.
  40. ↑ "2 Mode and service concepts". Transit Capacity and Quality of Service Manual. Transportation Research Board. 2013. p. 31/35. ISBN   978-0-309-28344-1.
  41. ↑ Vuchic, Vukan R. (14 February 2007). Urban Transit Systems and Technology. Wiley. p. 579. doi:10.1002/9780470168066. ISBN   978-0-471-75823-5 . Retrieved 15 August 2024.
  42. ↑ "Park Avenue Tunnel". 6 December 2012. Retrieved 15 October 2024.
  43. ↑ "38th Street" . Retrieved 15 October 2024.
  44. ↑ "First Car off the Earth: Allston Electric Goes into the subway on schedule time". The Boston Daily Globe. September 1, 1897. Archived from the original on 2005-08-29.
  45. ↑ Most, Doug (26 January 2014). "The bigger dig". Boston Globe. Retrieved 8 February 2023.
  46. 1 2 Zupan, Jeffrey; Pushkarev, Boris (1 November 1980). Urban Rail in America: An Exploration of Criteria for Fixed-Guideway Transit. U.S. Department of Transportation. Retrieved 20 June 2025.
  47. ↑ Berman, Jake (3 November 2023). The Lost Subways of North America: A Cartographic Guide to the Past, Present, and What Might Have Been. University of Chicago Press. ISBN   978-0-226-82980-7.
  48. ↑ Historic England. "Kingsway Tram Subway (northern section only) (Grade II) (1378792)". National Heritage List for England . Retrieved 15 February 2025.
  49. ↑ Geoffrey, Skelsey (2018). Brussels Metro to Grow As Pre-metro Shrinks. London Underground Railway Society. p. 3.
  50. ↑ "Call for big extension to underground". The Glasgow Herald. Retrieved 20 August 2025.
  51. ↑ "PREMETRO [1 record]". TERMIUM Plus®. 8 October 2009. Retrieved 9 February 2023.
  52. ↑ Transportation Research Board National Research Council (1989). Urban Public Transportation Glossary . Retrieved 16 February 2023. pre-metro: a light rail transit system designed with provisions for easy conversion to rail rapid transit
  53. ↑ Harman, Reg (2006). High speed trains and the development and regeneration of cities. London: Greengauge 21. p. 19. Köln, like other major German cities served by ICE services over high-speed lines, has a regional rail system (Schnellbahn) and a substantial tramway system, part operated as Stadtbahn (semi metro).
  54. ↑ Pedestrian Observations (29 October 2020). "Stadtbahn Systems" . Retrieved 16 February 2023.
  55. ↑ Ian Yearsley (21 December 1972). "Trams are coming back". New Scientist . Reed Business Information Ltd. Retrieved 17 January 2023. ... San Francisco and Boston, both with semi-metros and independent plans for new tramcars.
  56. ↑ Trikkestrategi (in Norwegian) (4 ed.). Oslo: Ruter As. 2011. p. 46.
  57. ↑ Landgraf, Robert J. (1992). "Cleveland's Light Rail System in the 1980s: The Ongoing Revolution". Transportation Research Record (1361): 259. ISSN   0361-1981 . Retrieved 22 March 2023.
  58. ↑ "St. Louis: MetroLink light rail reaching ridership targets 8 years early". www.lightrailnow.org. Retrieved 20 November 2024.
  59. ↑ "Tyne and Wear Metro". The Highway Engineer (23). Institution of Highway Engineers.: 44 1976. Retrieved 22 March 2023.
  60. ↑ "Regional editors". International Railway Journal: IRJ. (15). Simmons-Boardman Publishing Company: 18. 1975. Retrieved 3 May 2024. brake equipment to be fitted to 90 two-car articulated semi-metro trainsets, under construction by Duwag, for service in the municipal areas of Bonn, Cologne and Essen.
  61. 1 2 El Tráfico rodado y peatonal en Zaragoza: Una propuesta para su reestructuración (in Spanish). April 1982. Retrieved 17 November 2024.
  62. ↑ "The Hague". The Modern Tramway (30): 118. 1967. Retrieved 22 March 2023.
  63. ↑ Vogel, A. T. (December 1972). "The semi-metro plan for Den Haag". The Modern Tramway. 35 (35): 404. Retrieved 22 March 2023.
  64. ↑ Haring, Leonardus H. (September 2016). 13th National Light Rail and Streetcar Conference: Transforming Urban Areas. p. 401. ISBN   978-0-309-45059-1 . Retrieved 1 August 2023.
  65. ↑ "Transports publics urbains" (in French). Universite Montesquieu - Bordeaux IV. 28 January 2011. p. 85. Retrieved 12 January 2025.
  66. ↑ Oillo, Benoît (10 January 2020). La performance opérationnelle des systèmes de transport collectif en milieu urbain: définition et approche méthodologique (Thesis) (in French). Université Paris-Est. p. 39. Retrieved 12 January 2025.
  67. ↑ Ovenden, Mark (8 September 2020). Underground Cities: Mapping the tunnels, transits and networks underneath our feet. Frances Lincoln. p. 84. ISBN   978-1-78131-894-2 . Retrieved 8 April 2025.
  68. ↑ "Sistema de Metro Ligeiro do Porto" . Retrieved 22 March 2024.
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