London is credited with having the world's first underground railroad subway system, which opened in 1863.

Railroad subway systems are primarily designed to alleviate traffic congestion and provide efficient transportation within urban areas.

The cut-and-cover method involves excavating a trench, constructing the subway structure, and then covering it back up.

Platforms are the designated areas within underground stations where passengers board and disembark from subway trains.

New York City's subway system is the most extensive in the world, with over 472 stations and 24 lines.

Electric motors are the primary means of propulsion for railroad subway trains, providing efficient and environmentally friendly operation.

Hong Kong's Mass Transit Railway (MTR) was the first to implement a fare collection system using magnetic stripe cards in 1983.

An interlocking system is a complex network of tracks and switches that ensures the safe and efficient movement of subway trains.

The Tokyo Metro's Hibiya Line features a section that runs through an underwater tunnel beneath Tokyo Bay.

The contact rail is the electrified third rail that supplies power to subway trains through contact shoes mounted on the train's undercarriage.

The Moscow Metro is famous for its elaborate and visually stunning station designs, featuring artwork, sculptures, and architectural elements.

Tunnels are the underground passages through which subway trains operate, providing a dedicated and efficient transportation route.

The Chicago 'L' is famous for its elevated tracks that run above street level, providing a unique perspective of the city.

The signaling system is a complex network of signals and controls that ensures the safe and efficient operation of subway trains.

The Vancouver SkyTrain is renowned for its fully automated and driverless train operation, providing a seamless and efficient transportation experience.