Monorail

A monorail is a specific type of urban rail transit system. It uses a single rail or beam structure to move people.

This system is different from standard railways that use two parallel rails. Monorails have an intermediate transport capacity. This means they carry more people than a tram. However, they carry fewer people than a heavy rapid transit system. They are most often found in large cities, airports, or theme parks. While people often use the word "monorail" for any elevated train, it actually refers to the specific style of the track.

The way a monorail moves depends on its interaction with the guideway. A guideway is the beam that provides the track. Vehicles can either straddle the beam or be suspended from it. In a straddle design, the vehicle sits over the beam like a person sitting on a fence. In a suspended design, the vehicle hangs below the beam.

Modern mass transit systems often use the ALWEG beam and tire approach. In this setup, the vehicle is supported by one set of wheels and guided by another. Some systems also use linear induction motors to move. These motors use electromagnetic force to create motion. To handle curves, the vehicle bodies can connect to the beam via bogies. These are the undercarriage structures that hold the wheels.

Monorails are unique because they are always separated from other traffic. This is known as being grade-separated. Because of the geometry of the single rail, they do not share space with pedestrians or cars. This allows them to avoid red lights, intersection turns, and traffic jams.

This separation also makes them safer. Unlike buses or cars, monorails can only collide with other vehicles on the same system. They are also often quieter than diesel buses. They can obtain electricity directly from the track structure. This is different from other transit modes that might use a third rail or overhead power lines.

History shows that engineers have experimented with single rails for a long time. The first prototype was created in Russia by Ivan Elmanov in 1820. In 1876, the Centennial Monorail was shown at an exposition in Philadelphia.

Later, Charles Lartigue built a practical line in Ireland. It opened in 1888 and operated for 36 years until 1924. In the United States, the Boynton Bicycle Railroad ran in Brooklyn starting in 1890. It used a single load-bearing rail at ground level. Another early example was the Hotchkiss Bicycle Railroad in New Jersey in 1892. These early attempts helped engineers understand how to balance vehicles on one rail.

In the mid-20th century, monorail technology became more advanced. The Wuppertal monorail in Germany is a surviving suspended system. In the 1950s, the ALWEG straddle design emerged. This technology was later used by major manufacturers like Hitachi Monorail and Bombardier.

Disneyland in California opened the first daily operating monorail system in the U.S. in 1959. Since then, monorails have been seen as a futuristic way to travel. They are often used in amusement parks because they look and feel very modern.

Today, monorails are vital parts of many transit networks. The Tokyo Monorail is one of the busiest in the world. It has served over 1.5 billion passengers since it began in 1964. It averages about 127,000 passengers every single day.

China has also developed massive systems. The Chongqing Rail Transit uses a unique ALWEG-based design. These cars are much wider than most monorails. This allows them to have a capacity comparable to heavy rail. This is helpful in Chongqing because the city has many hills and rivers. In such places, building deep tunnels is very difficult.

Some modern systems even use maglev technology. Maglev stands for magnetic levitation.

Some maglev systems, like the Transrapid or Linimo, meet the definition of a monorail. However, they differ because they do not physically touch the beam while they move. They use magnets to float above the track. As cities face more traffic congestion, interest in monorails is growing again. Cities like Malta and Istanbul are currently investigating them as solutions for public transport.