Nepedia
Back to Discover
Advanced Reader
💻

Light rail

technology Maturity 7-9 Next article →

Light rail transit, often called LRT, is a specialized form of urban passenger rail. It uses rolling stock, or vehicles, derived from tram technology. However, it also incorporates certain features found in heavy rapid transit systems. The term "light" does not refer to the physical weight of the vehicles. Instead, it refers to the lighter infrastructure and capacity requirements needed. This makes light rail a flexible middle ground for urban transportation. It fills the gap between local bus services and massive heavy rail systems.

M Ocean View train at Forest Hill station, November 2018
M Ocean View train at Forest Hill station, November 2018

These systems function through various modes of operation and track types. A primary distinction is the right-of-way, which is the path the train follows. Some light rail operates in mixed street traffic alongside cars and buses. Other systems use an exclusive right-of-way, meaning they have their own private tracks. Some networks are even fully grade-separated, meaning they do not cross paths with road traffic. When these systems are completely separated from streets, they are called light metros or light rail rapid transit (LRRT).

KVB5208 Neußer Straße Gürtel
KVB5208 Neußer Straße Gürtel

The vehicles themselves follow specific technical designs to move efficiently. Most light rail vehicles are electric and draw power from overhead lines. They use a device called a pantograph or a trolley pole to connect to these lines. These vehicles are operated by an onboard driver. They can run as individual tramcars or as multiple units coupled together into longer trains. Depending on the design, they may feature high-platform boarding or low-floor boarding for easier access.

Coming in on the priority track (4283902657)
Coming in on the priority track (4283902657)

History shows that light rail evolved from much older streetcar and tramway systems. In the late 19th century, cities like New York and Boston moved tramways underground to reduce congestion. The Tremont Street subway in Boston, opened in 1897, was a major precursor. Many traditional streetcar systems were closed after the 1950s as investment shifted to cars. However, modern light rail developed largely in postwar West Germany. There, many cities upgraded their existing tram networks into Stadtbahn systems. These "city railroads" featured high-capacity vehicles and dedicated alignments.

Huntington Avenue streetcar at Park Street station, 1897
Huntington Avenue streetcar at Park Street station, 1897

The official term "light rail" was introduced in 1972 in the United States. The U.S. Urban Mass Transportation Administration (UMTA) created the term to describe modernized systems. They wanted an English equivalent for the German word Stadtbahn. The first new generation of light rail in North America opened in Edmonton, Alberta, in 1978. These vehicles were German Siemens-Duewag U2 models. This successful launch inspired many other cities to build similar systems.

Edmonton LRT testing commerical c.1978
Edmonton LRT testing commerical c.1978

Since the 1980s, light rail has expanded globally across many different continents. In North America, the San Diego Trolley became a model after opening in 1981. Between the 1990s and 2010s, the number of U.S. systems roughly doubled. This included expansions in cities like Portland, Los Angeles, and Seattle. In Europe, cities like Nantes and Manchester reopened or built new networks. Expansion has also reached Africa and Asia. For example, Addis Ababa, Ethiopia, opened its light rail in 2015.

ET Addis asv2018-01 img07 Light Rail (cropped2)
ET Addis asv2018-01 img07 Light Rail (cropped2)

Light rail is unique because of its extreme operational flexibility. A single line can change its character as it moves through a city. It might run as a tram on a street, then go underground in a tunnel. It could then transition to an elevated viaduct. The Los Angeles Metro Rail's A Line is a notable example of this. It features sections that act as a tramway, a light metro, and rapid transit. This ability to adapt allows cities to move large numbers of people efficiently.

578 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (20)
File:Metrolink tram at Lower Moseley Street..jpg
Metrolink tram at Lower Moseley Street..jpg
File:SEPTA Light Rail.jpg
SEPTA Light Rail.jpg
File:CTA Skokie Swift, Skokie, IL in May 1964 (25819535271).jpg
CTA Skokie Swift, Skokie, IL in May 1964...
File:Edmonton LRT testing commerical c.1978.jpg
Edmonton LRT testing commerical c.1978.jpg
File:ET Addis asv2018-01 img07 Light Rail (cropped2).jpg
ET Addis asv2018-01 img07 Light Rail...
File:20230425 De Lijn 6138.jpg
20230425 De Lijn 6138.jpg
File:Stadtbahn Essen U17 5234 Berliner Platz 1910040748.jpg
Stadtbahn Essen U17 5234 Berliner Platz...
File:Cappel Stadtbahn02 2005-12-30.jpg
Cappel Stadtbahn02 2005-12-30.jpg
File:DulwichGroveStop.jpg
DulwichGroveStop.jpg
File:Tram at the Circular Quay light rail stop December 2019 (cropped).jpg
Tram at the Circular Quay light rail stop...
File:KVB5208 Neußer Straße Gürtel.JPG
KVB5208 Neußer Straße Gürtel.JPG
File:Huntington Avenue streetcar at Park Street station, 1897.jpg
Huntington Avenue streetcar at Park...

+ 8 more

More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.