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Light rail or light transit（LRT）is a particular class of urban and suburban passenger railway that uses equipment and infrastructure that is generally less massive than that used for rapid transit systems，with modern light rail vehicles usually running along the system.

Light rail systems can handle steeper inclines than heavy rail，and curves sharp enough to fit within street intersections.They are generally built in urban areas，providing frequent service with small，light trains or single cars.

A few light rail networks tend to have characteristics closer to rapid transit or even commuter rail，some of these heavier rapid transit-like systems are referred to as light metros.Other light rail networks are tram-like in nature and partially operate on streets.Light rail systems are found throughout the world，on all inhabited continents.They have been especially popular in recent years due to their lower capital costs and increased reliability compared to heavy rail systems.

The term“light rail”is derived from the British English term light railway long used to distinguish tram operations from steam railway lines，and also from its usually lighter infrastructure.

The light rail systems built in the 19th and early 20th centuries generally only ran in single-car setups.

In North America，many of these original light rail systems were decommissioned in the 1950s and onward as the popularity of the automobile increased.

Beginning in the1980s，some cities began reintroducing light-rail systems that are more like subway or metro systems that operate at street level.These light-rail systems include modern，multi-car trains that can only be reached at stations that are spaced anywhere from a couple blocks to a mile or more apart.Some of these systems operate within roadways alongside automobile traffic，and others operate on their own separate right-of-way.