
The table gives information about the underground railway systems in four cities, covering their opening dates, route lengths and annual passenger numbers.
Overall, the oldest and longest systems are not necessarily the busiest: Tokyo's network, though shorter than two of the others, carries by far the most passengers, whereas Dubai's young system is the smallest on every measure.
London's underground is both the oldest and the most extensive, having opened in 1863 and grown to 402 kilometres of route. Yet its 1,200 million annual passengers place it only third for usage. Tokyo, which opened some sixty years later with a network of 305 kilometres, transports 3,200 million people a year—nearly three times the London figure and easily the highest in the table.
The two newer systems differ sharply from one another. Delhi's metro, dating from 2002, already stretches 390 kilometres—almost matching London—and carries 1,800 million passengers annually. Dubai's system, by contrast, opened in 2009 and remains modest in scale, with 90 kilometres of track and 200 million passengers, roughly a sixteenth of Tokyo's total.