Subway Systems of the World

London's Metropolitan Railway opened on January 10, 1863, making it the world's first underground passenger railway. It initially ran between Paddington and Farringdon using steam locomotives.

The Moscow Metro, opened in 1935, is often called a collection of 'underground palaces' due to its ornate stations featuring chandeliers, marble columns, mosaics, and sculptures in the Socialist Realist style.

The Beijing Subway is the busiest metro system in the world by annual ridership, carrying over 3.8 billion passengers per year. It has expanded rapidly since 2000 and now has over 800 km of track.

The New York City Subway operates 24 hours a day, 7 days a week, making it one of the few subway systems in the world to provide round-the-clock service. It has been running since 1904.

Stockholm's metro (Tunnelbana) is often called the 'world's longest art gallery.' Many stations are carved from bedrock and left with exposed cave-like walls, decorated by over 150 artists with paintings, mosaics, and installations.

The third rail is an electrified rail that runs alongside the track and provides electrical power to subway trains. Trains collect power from it via a contact shoe. It typically carries 600-750 volts of direct current.

Several Paris Metro lines use trains that run on rubber tires instead of traditional steel wheels on rails. This system, introduced in the 1950s, provides better acceleration, braking, and reduced noise.

The New York City Subway has the most stations of any metro system in the world, with 472 stations. While other systems may have more track length or ridership, NYC leads in total number of stations.

The Circle Line is a London Underground line that connects many of London's major railway terminals in a loop shape. Originally formed in 1884, it runs through stations including Paddington, King's Cross, and Liverpool Street.

The Dubai Metro is one of the world's longest fully automated driverless metro networks. Trains operate without drivers, using advanced computer systems to control speed, stops, and door operations.

Harry Beck's 1931 London Underground map simplified the network into a diagram with straight lines and uniform spacing. This revolutionary design influenced transit maps worldwide and is still the basis of the Tube map today.

The Pyongyang Metro has stations that are approximately 110 meters (360 feet) deep, among the deepest in the world. The depth was reportedly designed to serve as a nuclear bomb shelter during the Cold War.

Platform screen doors are barriers between the platform and the tracks that open only when a train has stopped. They prevent accidental falls and intentional entry onto tracks, and also improve climate control in stations.

Tokyo's metro system is renowned for its extraordinary punctuality, with the average delay being approximately 18 seconds. The system carries over 8 million passengers daily across multiple operators.

The earliest London Underground lines were built using the 'cut and cover' method: digging a trench along existing streets, building the tunnel structure, and then covering it over. This was cheaper than deep tunneling but highly disruptive.