A medium-capacity system (MCS), also known as light rapid transit or light metro, is a rail transport system with a capacity greater than light rail, but less than typical heavy-rail rapid transit.[1] MCS trains are usually 1 to 4 cars. Most medium-capacity rail systems are automated or use light-rail type vehicles.
Since ridership determines the scale of a rapid transit system, statistical modeling allows planners to size the rail system for the needs of the area. When the predicted ridership falls between the service requirements of a light rail and heavy rail or metro system, an MCS project is indicated. An MCS may also result when a rapid transit service fails to achieve the requisite ridership due to network inadequacies (e.g. single-tracking) or changing demographics.
In contrast with light rail systems,[2] an MCS runs on a fully grade separated exclusive right-of-way. In some cases, the distance between stations is much longer than typically found on heavy rail networks. An MCS may also be suitable for branch line connections to another mode of a heavy-capacity transport system, such as an airport or a main route of a metro network.
The definition of a medium-capacity system varies due to its non-standardisation. Inconsistencies in international definitions are even reflected within individual countries. For example, the TaiwanMinistry of Transportation and Communications states that each MCS system can board around 6,000 to 20,000 passengers per hour per direction (p/h/d or PPHPD),[3] while the Taiwan Department of Rapid Transit Systems (TCG) suggests an MCS has a capability of boarding around 20,000 to 30,000 p/h/d,[4] and a report from the World Bank places the capacity of an MCS at 15,000 to 30,000 p/h/d.[5] For comparison, ridership capacity of more than 30,000 p/h/d has been quoted as the standard for metro or "heavy rail" standards rapid transit systems,[6] while light rail systems have passenger capacity volumes of around 10,000 to 12,000 p/h/d[5] or 12,000 to 18,000 p/h/d.[6]VAL (Véhicule Automatique Léger) systems are categorised in the medium-capacity rail systems because their manufacturer defines their passenger capacities as being up to 30,000 p/h/d.[7] In Hong Kong, MTR's Ma On Shan line could, in some contexts, are classified as a medium-capacity system (as it used shorter 4-car SP1950 trains, compared to 7- to 12-car trains on other heavy rail lines) but can attain up to 32,000 p/h/d which is comparable to the passenger capacity of some full metro transit networks.[8] However, it was built to the full heavy rail standard as it was designed to be extended. Full-length, 8-car trains were deployed on the line in advance of its extension and the line was extended into the Tuen Ma line in June 2021. Two other lines, the Disneyland Resort lineshuttle service to Hong Kong Disneyland Resort since 2005 and the South Island line since December 2016, are also classified as MCS because of their shorter trains and smaller capacity, however they use the same technology as the full-capacity rapid transit lines.
Generally speaking, medium capacity designation is created from relative lower capacity and/or train configuration comparisons to other heavy rail systems in the same area. For example, the train in an MCS may have a shorter configuration than the standard metro system, usually three (though, in some cases, just two) to six traincars, allowing for shorter platforms to be built and used. Rather than using steel wheels, rubber-tyred metro technology, such as the VAL system used on the Taipei Metro, is sometimes recommended, due to its low running noise, as well as the ability to climb steeper grades and turn tighter curves, thus allowing more flexible alignments.
Fully heavy rail or metro systems generally have train headways of 10 minutes or better during peak hours.[9] Some systems that qualify as heavy rail/metro in every other way (e.g. are fully grade separated), but which have network inadequacies (e.g. a section of single track rail) can only achieve lesser headways (e.g. every 15 minutes) which result in lower passenger volume capacities, and thus would be more accurately defined as "light metro" or "medium-capacity" systems as a result. An example is the LA Metro B/D line during the COVID-19 pandemic, as headways were reduced to every 12-20 minutes on each line.
In addition to MCS, light metro is a common alternative word in European countries, India,[10][11] and South Korea.[12]
Ui-Sinseol Line train leaving Solbat Park station in Seoul, South Korea
In some countries, however, light metro systems are conflated with light rail. In South Korea, light rail is used as the translation for the original Korean term, "경전철" – its literal translation is "light metro", but it actually means "Any railway transit other than heavy rail, which has capacity between heavy rail and bus transit".[13][14][15][16] For example, the U Line in Uijeongbu utilises VAL system, a variant of medium-capacity rail transport, and is therefore categorised "light metro" by LRTA and others,[12] though the operator itself and South Korean sources refer to the U Line as "light rail".[17]Busan–Gimhae Light Rail Transit is also akin to a light metro in its appearance and features, thought the operator refers it as a "light rail".[18] Likewise, Malaysian officials and media commonly refer to the Kelana Jaya, Ampang and Sri Petaling lines as "light rail transit" systems;[19][20][21] when originally opened, the original Malay abbreviations for the lines, PUTRA-LRT (Projek Usahasama Transit Ringan Automatik/Automatic Light Transit Joint Venture Project) and STAR-LRT (Sistem Transit Aliran Ringan/Light Flow Transit System) did not clearly distinguish between light rail and light rapid transit. Some articles in India also refer to some "light metro"-type systems as "light rail".[22] The Light Rail Transit Association (LRTA), a nonprofit organisation, also categorises several public transport systems as "light metro".[23][a]
Advantages and disadvantages
The main reason to build a light metro instead of a regular metro is to reduce costs, mainly because this system employs shorter vehicles and shorter stations.
Light metros may operate faster than heavy-rail rapid transit systems due to shorter dwell times at stations, and the faster acceleration and deceleration of lighter trains.[citation needed] For example, express trains on the New York City Subway are about as fast as the Vancouver SkyTrain, but these express trains skip most stops on lines where they operate.
Medium-capacity systems have restricted growth capacities as ridership increases. For example, it is difficult to extend station platforms once a system is in operation, especially for underground railway systems, since this work must be done without interfering with traffic. Some railway systems, like Hong Kong and Wuhan, may make advance provisions for longer platforms, for example, so that they will be able to accommodate trains with more, or longer cars, in the future. Taipei Metro, for example, constructed extra space for two extra cars in all its Wenhu Line stations.
The following is the list of currently-operating MCSs which are categorised as light metros by the Light Rail Transit Association (LRTA) as of March 2018[update],[24] unless otherwise indicated.
The list does not include, for example, monorails and urban maglev, despite most of them also being "medium-capacity rail system".
Low-floor trains T and T1 built by Bombardier Transportation, 27.3 metres (90 ft) and 26.8 metres (88 ft) long respectively, are operated in 2- or 4-car configurations.
While using equipment typically employed in light rail systems, the Confederation Line approaches the capacity of a full "light metro" system since it operates with a 2-car (100-metre long) Alstom Citadis Spirit trains.
While using equipment typically employed in medium-capacity systems, the Expo line approaches the capacity of a full "rapid transit" system since it operates with longer 4- and 6-car Bombardier Innovia Metro trains. However, the Canada Line operates with 2-car Rotem trains.
Capital Airport Express uses 4-car L-type trains, 60m long. Yanfang line uses 4-car B-type trains, 76 metres (249 ft) long, with trains from both lines being driverless.
Lines 4 and 6 use 4-car L-type trains, 67m long. Guangfo line uses 4-car B-type trains, 76 metres (249 ft) long. Zhujiang New Town Automated People Mover uses 14 Bombardier Transportation's APM 100 cars built in Pittsburgh, Pennsylvania.[29]
Trains: 4 compartments without drivers. Some[clarification needed] of the M-Train cars used in the Disneyland Resort line were originally ordered from 1994–1998 as subtype H-Stock train (Phase 3 EMU, A/C 270–291, B/C 486–496). Units A/C274 A/C281 A/C284 A/C289 A/C291 and B/C490 are now used on the Disneyland Resort line.
Uses Mitsubishi Heavy IndustriesCrystal MoverAPM vehicles with rubber tyres running on concrete tracks.[32] Mitsubishi supplied 55 two-car trains that are fully automated (driverless) and utilise a rubber-tyred APM system.[33] They have a capacity of up to 476 passengers.[32]
VALpeople mover system. Trains: 2-car configuration, 26 metres (85 ft) in length, with a passenger capacity of 208–240 per train (depending on VAL 206 or VAL 208 train). UrbanRail.net describes it as a "new generation of metro systems".[34]
Driverless vehicle system. The line is designed to carry up to 30,000 passengers per hour.[37][38][39] Several articles define the system as "light metro".[37][38][39]
Generally considered to be a "light metro" considering its low frequency, limited hours of operation and reduced transport capacity. It is actually categorised as "light rail" by LRTA.
Trains:Port Island Line and Rokkō Island Line. Both consist of 4-car configuration (300 people per train), but the platforms are made for fitting to 6-car configuration.
Trains: Line began with 2-car configuration, reconfigured to 3-car in 1999,[47] and procured new 4-car trains in 1999,[47] 2006, and 2022.[48] Line was originally designed for 18,000 p/h/d capacity,[47] increased to 40,000 p/h/d in 2006.[49] Categorised as "light rail" by LRTA.[50]
Trains: 3-car configuration, with a max. capacity of 1,182 passengers, and running with 3.5–4 minute headways. 4-car trains with a max. capacity of 1,576 passengers were introduced in 2022.[51] However, line is designed for 23,000 p/h/d capacity, expandable to 48,000 p/h/d.[52]
Mostly underground line operates with just 15-minute headways and 2-car trains (306 passengers max.); one reference[56] even categorises line as "light rail".
Operates on a private primarily surface-level "right-of-way" with partial triple-tracking, allowing for peak express services. Has been categorised by APTA as being "Light rapid rail transit"[62] (i.e. between "rapid transit (heavy rail)" and "light rail"). While it has high platforms and third rail power, all intermediate stops are flag stops and fares must be paid to the operator upon boarding except at the termini. This makes it difficult to categorise, as it has the infrastructure and rolling stock of a light metro but is operated in many ways like a trolley or bus service.
Line 3 Scarborough – Categorised by APTA as being "intermediate rail" (i.e. between "heavy rail" and "light rail"),[64] and categorised as a "light metro" by LRTA.[24] Scheduled to cease operations in November 2023, service was suspended following a derailment in July 2023 and was not resumed, instead being replaced by an express bus service.[65]
^The French term Métro léger, a literal translation of "light metro", means light rail.
References
^Allport, Roger (1996). "Theme Paper 6: Investment in mass rapid transit"(PDF). In Stares, Stephen; Zhi, Liu (eds.). China's Urban Transport Development Strategy: Proceedings of a Symposium in Beijing, November 8–10, 1995. Washington D.C.: The World Bank. p. 257. Retrieved 31 August 2015.
^"上海首条胶轮APM浦江线 3月31日起通车试运营". 上海地铁 (in Chinese (Taiwan)). Archived from the original on 2018-03-27. Retrieved 2021-09-23. 在轨道交通选型上，采用中运量 (MCS)、胶轮转向轨制式、噪音相对小、启停加减速快捷等特点的APM全自动无人驾驶系统
