Light Rail as a Modern Solution for Large Cities

(1) Big cities worldwide face the same problem. The capacity of the street network is not enough for cars, trams and buses, while underground systems are too massive and expensive outside the city centre. Light rail combining the benefits of a tram, metro and commuter train is seen as a modern solution of this eternal problem of city congestion.

(2) Conventional rail technologies including high-speed, freight, commuter/regional, and metro/subway/elevated urban transit systems are considered to be ‘heavy rail’.

Light rail or light rail transit (LRT) is a form of urban rail public transportation that generally has a lower capacity and speed than heavy rail, but higher capacity and speed than traditional street-running tram systems. The term LR was devised in 1972. ‘Light’ in this context is used in the sense of ‘intended for light loads and fast movement’, rather than referring to physical weight, since the vehicles often weigh more than those on the so-called heavy rail systems. The investment in infrastructure is also usually lighter than would be found for a heavy rail system.

(3) Modern light rail technology has primarily German origin because the Germans did not destroy the tramway systems as had happened especially in USA and UK after World War II, but developed them into model light rail systems (Stadtbahnen). All large and most medium-sized German cities maintain light rail networks.

(4) There are two general types of LR. Firstly there is the traditional type where trains run along the streets sharing space with road traffic (usually in the dense city centre). And secondly there is the type where trains run along their own right-of-way and are separated from road traffic, but still have to comply with traffic laws. There are many LR systems which have a combination of the two, with both on road and off road sections. LR can also be elevated or routed through tunnels where the street area is already used. A combination of these is used to match local conditions and helps to increase both the capacity and the speed of LR.

(5) In practice, LR is characterized by the following features.

• It works in the tunnels as a metro.

• On its own right of way it works like a train.

• On the streets it works like a traditional tramway or a bus.

• On the market squares and other pedestrian areas it works much like an old fashion slow streetcar or coach.

(6) LR usually operates electric trains since they are fast, quiet, and non-polluting. These trains may be powered with overhead cables, or through the use of a third rail. LR is often networked with commuter rail, subway, and buses. It usually runs at set intervals or times to match other means of transport.

(7) The main advantage of LR is that it is cheaper and more flexible since it can be operated on the road with mixed traffic. It has a much simpler signalling than heavier rail systems, often relying on the driver. When it is running along a highway it can be given priority at signalized junctions.

(8) A derivative of LRT is Light Metro. Such railways are characterized by exclusive rights of way, advanced train control systems, short headway capability, and floor level boarding. These systems approach the passenger capacity of full metro systems, but can be cheaper to construct.

(9) It’s hard to find a city in America or Europe that isn’t planning, proposing, studying or actually building a LR system. There are now more than 400 LR systems in about 50 countries, with a further 100 planned.