Urban Research: Modern Light Rail as a transport solution for large cities

Thursday, January 12, 2012

Modern Light Rail as a transport solution for large cities

by Antero Alku

Large cities are typically very tightly built in the city centres, which are surrounded with a large circle of suburban having much less buildings an population per area. This causes a problem for choosing a transport system. What is suitable in city centres – like underground metro systems – is too massive and expensive outside the city centre.

This phenomenon was found in Europe and USA in 1960’s, when private car traffic from suburban started to fill the cities. Very soon it was found, that the capacity of the street network is not enough for cars, trams and buses. Existing metro networks were able to manage the city transport where metros were already built, but were not suitable to extend outside the central city area.
As population density is the key factor for choosing a public transport system, the problem was, that the operation capacity of the traditional tramways (street cars) and buses does not overlap the metro's operation capacity. A bus systems capacity on one street is 2000 passengers per hour max, when a metro line is already uneconomical to operate at 2500 passengers per hour.
The solution was found in Germany, which did not destroy the tramway systems as had happened especially in USA and UK. Existing tramway systems were developed to fill higher standard than just a local bus like transport system on the streets. The benefits of a tram, metro and commuter trains was combined to one system. This kind of a tramway system was named as Light Rail in English.