Subway
Overview
The subway (地下鐵, subway/metro) is a high-capacity, high-speed transport system connecting the interior and outskirts of a city, and generally refers to an urban rail system that operates through a mixture of underground tunnels and at-grade or elevated sections. Since the world's first commercial service began in London in 1863, hundreds of cities today treat the subway as the backbone of urban transport. Beyond being a mere means of travel, the subway functions as core infrastructure that determines a city's spatial structure, real estate values, commuting culture, and even its economic productivity.
Main Content
Concept and Scope
The subway is a subcategory of urban rail and refers to city-type railways with a high proportion of underground sections. In the English-speaking world, it is called subway (United States), underground/tube (United Kingdom), metro (Europe and Asia), U-Bahn (Germany), and so on, depending on the city. It is distinguished from light rail, trams, and regional rail by operating scope and transport capacity, but recently there has been a trend toward convergence between regional express rail and urban rail through transfer and through-running services.
History
- In 1863, the London Metropolitan Railway opened using steam locomotives, becoming the world's first subway.
- In 1890, the City and South London Railway introduced the first electric-traction subway.
- Budapest in 1896, the Paris Métro in 1900, and the New York City Subway in 1904 opened in succession.
- In 1927, the Tokyo Ginza Line opened as Asia's first subway.
- South Korea built the Seoul Metropolitan Subway network beginning with the opening of Seoul Subway Line 1 in 1974, and after the 1990s it spread to metropolitan cities such as Busan, Daegu, Incheon, Gwangju, and Daejeon.
- After the 2000s, China expanded routes in Beijing, Shanghai, Shenzhen, and elsewhere at the fastest pace in the world.
Technical Composition
Subway construction is broadly divided into cut-and-cover, NATM (the New Austrian Tunnelling Method), and TBM (tunnel boring machine). In city-center sections, TBMs are mainly used to minimize ground settlement. The operating system consists of track, power supply method (third rail or overhead catenary), signal control, and rolling stock, and signaling has evolved through ATS and ATP to communication-based train control (CBTC). The introduction of CBTC has made it possible to reduce train headways to tens of seconds, and fully unattended operation at GoA4 level has also been commercialized.
Operations and Fare Systems
The Seoul metropolitan rail network operates a distance-proportional fare system and an integrated transfer discount system, and provides various payment methods such as transit cards, mobile tags, and period passes (including unlimited types). Headways, express and local operation, and transfer route design are optimized to match each city's usage patterns. Recently, demand-based flexible scheduling and real-time crowding information provision have been spreading.
Safety and Facilities
Platform screen doors have become standard equipment that reduces fall accidents and train-induced wind. Smoke exhaust facilities, evacuation passages, earthquake detection and automatic stop systems, and emergency power for outages are also essential elements for fire response. Air quality management within stations, noise reduction, and ensuring accessibility for passengers with reduced mobility, such as elevators and escalators, are major items in recent safety regulations.
Urban and Social Impact
The subway shortens commuting times, enabling the spatial expansion of urban areas, and reorganizes commercial and residential locations through transit-oriented development (TOD). Real estate price premiums near stations, transport equity, and gaps in user experience according to crowding are representative socioeconomic issues created by the subway.
Latest Trends
With the opening of the Suseo–Dongtan section of the Seoul Metropolitan Area Great Train eXpress (GTX)-A line in March 2024, the regional transport landscape is changing rapidly, and construction of the GTX-B and C lines and discussions on extensions are continuing. Seoul Metro is pursuing signal system upgrades, expanded unattended operation, AI-based crowding prediction, and advanced real-time train arrival information. Monthly flat-rate public transit passes such as the Climate Card introduced in 2024 are also spreading, while fare increases and deficit coverage remain major policy challenges. Overseas, the Riyadh Metro in Saudi Arabia opened in 2024, and new line construction in India and Southeast Asia is active. In addition, the revival of trams and light rail, a shift toward rail-centered transport to reduce carbon, and fourth-generation signaling systems based on autonomous driving are cited as key keywords for 2025 and beyond.
Related Topics
- [[Urban Rail]]
- [[GTX]]
- [[Transit Card]]
- [[Platform Screen Doors]]
- [[Public Transit]]