With more than 1,000 kilometers of track in service, the New York subway , opened in 1904, is the longest subway network in the world . Millions of people travel through it every day.
The metro that supports a greater human flow is the Moscow metro, with about 2,600 million passengers per year, the second most used being that of the capital of Japan, with about 2,500 million passengers per year. In the case of Tokyo, each convoy in the Japanese capital has 8 wagons capable of transporting 150 people each. This allows 2,400 travelers to take it at peak times.
The London tube , inaugurated in 1890, is not only the oldest, but it is the second longest (more than 400 kilometers km).
In Spain, the Madrid metro was launched on October 17, 1919. At present, for its more than 280 kilometers in length of its lines, millions of daily trips are made. Its size, excluding the light rail lines, make it the eighth largest subway line in the world.





