This list includes electrified rapid transit train systems from around the world. In different countries, these systems are sometimes called subways, undergrounds, tubes, mass rapid transit (MRT), métro, or U-Bahn. As of April 10, 2026, 213 cities in 63 countries operate 948 metro lines.
The London Underground began as an underground railway in 1863. Its first electrified line, the City and South London Railway, opened in 1890. This made it the world’s first deep-level electric metro system. The Budapest Millennium Underground Railway, which opened in 1896, was the first electric underground railway built specifically for city travel. It is still in use today. The Beijing Subway is the longest metro network, covering 879 kilometers (546 miles), and it is the busiest, with about 2.83 billion passenger trips each year. As of 2024, China has the most metro systems, with 54 in operation. This includes 11 of the 12 longest metro networks in the world.
Considerations
The International Association of Public Transport (L'Union Internationale des Transports Publics, or UITP) describes metro systems as urban passenger transport systems that "operate on their own special path and are separated from regular roads and pedestrian traffic." The terms "heavy rail" (commonly used in North America) and "heavy urban rail" are similar to the term "metro." Heavy rail systems are specifically defined as "electric railways."
It can be hard to tell the difference between metro systems and other types of public transport, such as light rail and commuter rail. The UITP only separates "metros" from "light rail," while the American Public Transportation Association (APTA) and Federal Transit Administration (FTA) distinguish all three types. A common way to tell the difference between metro and light rail is by how they are separated from other traffic. Light rail systems may share roads with cars or use tracks that cross roads at the same level, while metro systems usually run on a special path that is separated from other traffic and has no access for vehicles or pedestrians.
Compared to commuter rail or light rail, metro systems are mainly used for travel within a city. They also have more frequent service and can carry more passengers. Most metro systems do not share tracks with freight trains or trains that travel between cities. The type of wheels used (steel or rubber) or the power source (third rail or overhead lines) does not affect how the system is classified.
The name of the system is not used to decide if it is included or excluded. Some cities use "metro" as a brand name for a transit line that is not a rapid transit system. Similarly, some systems called "light rail" meet all the requirements for being a rapid transit system. Some systems also include light metro or light rail lines as part of a larger network under the same name. These systems are listed, but the light rail lines are not counted in the network data.
Some transit networks may have the same service quality as metro systems but extend far beyond the city and are sometimes called S-Bahn, suburban, regional, or commuter rail. These are not included in this list. Neither are funicular systems or people movers, such as those found in amusement parks, ski resorts, or airports.
This list counts separate metro systems in a city or area if they are owned or operated by different companies. This list does not aim to show the full size or scope of a city's total rapid transit network. The data in this list should not be used to estimate the size of a city's, region's, or country's urban rail transit systems or to create rankings.
List
This list can be sorted. Click on the icon in the column header to change how the list is sorted. Note: Please be aware that this list might not show all information accurately, as some systems display yearly ridership numbers from the year when the pandemic happened, while others show numbers from years before the pandemic.
Under construction
The following list shows new metro systems around the world that are being built right now. In some cases, it is not certain if the system will be a complete metro system when it starts working. Only metro systems that are being built are included. These are cities that do not have any existing metro systems.
The countries of Ivory Coast, Israel, and Serbia are building their first ever metro systems.
References
- the ridership includes "Domestic Service", "Airport Express" and "Cross-boundary";
- "Intercity, Light Rail & Bus" and "High Speed Rail (HSR)" are excluded from the counts.