Light rail

Gold Line train on East 1st Street, July 2017

Green line Trax at Gallivan Plaza

Calgary Transit Siemens S200

El Mourouj line By Ma7mix - panoramio

StreetCarSRM

Metrolink light rail @ Central West

Light rail or light rail transit (LRT) is a form of urban rail transit that utilizes equipment and infrastructure that is less heavy than traditional commuter rail and metro systems. It is characterized by its ability to operate in mixed traffic, its use of electrically powered rail cars, and its provision of a service that is more frequent than traditional heavy rail but less so than a metro system. Light rail systems are designed to offer a compromise between the higher capacity and speed of heavy rail and the flexibility and lower cost of bus transit.

History

The concept of light rail began in the late 19th century with the advent of streetcars and tram systems in urban centers, which were initially horse-drawn and later electrified. The evolution of light rail began as these systems were upgraded in the mid-20th century to handle greater capacities and operate on exclusive right-of-ways, distinguishing them from slower, street-running vehicles. The term "light rail" was adopted in the 1970s in the United States to describe these upgraded systems that were designed to be a more cost-effective form of rapid transit.

Characteristics

Light rail systems typically share several key characteristics:

• Electrically powered vehicles: Most light rail systems use electric vehicles that draw power from overhead catenary wires.
• Exclusive right-of-way: While light rail can operate in mixed traffic, many systems have segments of track that are exclusive to them, which helps to improve speed and reliability.
• On-street operation: Unlike heavy rail, light rail systems can operate within city streets, allowing them to serve densely populated urban areas directly.
• Lower capacity and speed than heavy rail: Light rail systems are designed for shorter distances with more frequent stops, making them slower and of lower capacity than heavy rail systems but more adaptable to urban environments.
• Accessibility: Light rail stations are typically more accessible than heavy rail stations, with shorter platforms and more frequent stops.

Infrastructure

Light rail infrastructure includes the tracks, electrification systems, stations, and signaling required to operate the service. Tracks may be laid in dedicated rights-of-way, within city streets, or along existing rail corridors. Stations are generally simpler and less expensive to construct than those for heavy rail, often consisting of platforms with shelters rather than enclosed buildings.

Advantages

Light rail systems offer several advantages over other forms of urban transit:

• Flexibility: Light rail can operate in a variety of environments, from dense urban areas to suburban corridors.
• Cost-effectiveness: The infrastructure and vehicles for light rail are generally less expensive than those required for heavy rail systems.
• Environmental benefits: Electrically powered light rail vehicles produce fewer emissions than buses or cars, contributing to cleaner air in urban areas.
• Urban development: Light rail systems can stimulate economic development along their corridors, encouraging higher-density, transit-oriented development.

Challenges

Despite its advantages, light rail faces several challenges:

• Funding: The initial capital costs of building light rail systems can be high, making funding a significant challenge.
• Integration: Integrating light rail with existing transportation systems and ensuring seamless transfers can be complex.
• Right-of-way issues: Securing exclusive right-of-way in densely populated areas can be difficult and expensive.
• Competition with other modes: Light rail must compete with cars, buses, and other forms of transit for passengers and public support.

Examples

Notable examples of light rail systems include the Portland MAX, the San Francisco Muni Metro, and the Toronto streetcar system. These systems exemplify the adaptability of light rail to different urban environments and the role it can play in enhancing urban mobility.