Light railways

Light railway is a railway built at lower costs and to lower standards than typical "heavy rail"; it uses lighter-weight track, and is more steeply graded and tightly curved to avoid civil engineering costs. These lighter standards allow lower costs of operation, at the price of slower operating speeds and lower vehicle capacity.

In countries where a single standard gauge is dominant, the term light railway does not imply a narrow gauge railway. Most such narrow gauge railways operate as light railways, but not all light railways need be narrow gauge. After Spooner's development of steam-haulage for narrow gauge railways the prevailing view was that the gauge should be tailored according to the traffic, "the nearer the machine is apportioned to the work it has to do the cheaper will that work be done". From the 1890s though it was recognised that cost-savings could be made in construction and operation of a standard gauge railway, "light axle-loads and low speeds, not gauge, are the first condition of cheap construction and economical working. Gauge is quite a secondary factor."Break of gauge now became an important factor and there was much concern over whether this would become an additional cost for the transhipment of goods, or whether this was over-emphasised compared to the amount of warehousing and handling needed anyway. The Irish railway system in particular became a good example of a broad gauge main line system with many independent narrow gauge, 3 ft (914 mm), light railway feeder branch lines.

The precise meaning of the term varies by geography and context.

In the United States, "light railway" generally refers to an urban or interurban rail system, which historically would correspond to a streetcar network. The distinct term light rail was introduced in the 1970s to describe a form of urban rail public transportation that has a lower capacity and lower speed than a heavy rail or metro system, but which generally operates in exclusive rights-of-way thus making it distinct from streetcar systems which operate in shared road traffic with automobiles. Urban sprawl combined with higher fuel prices has caused an increase in popularity of these light rail systems in recent decades.

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