By annual ridership, the New York City Subway is the busiest rapid transit system in both the Western Hemisphere and the Western world, as well as the eleventh-busiest rapid transit rail system in the world.[18] The subway carried 1,793,073,000 riders in 2022.[6]: 2 [note 5] On October 29, 2015, more than 6.2 million people rode the subway system, establishing the highest single-day ridership since ridership was regularly monitored in 1985.[20]

The system is also one of the world's longest. Overall, the system contains 248 miles (399 km) of routes,[10] translating into 665 miles (1,070 km) of revenue track[10] and a total of 850 miles (1,370 km) including non-revenue trackage.[11] Of the system's 28 routes or "services" (which usually share track or "lines" with other services), 25 pass through Manhattan, the exceptions being the G train, the Franklin Avenue Shuttle, and the Rockaway Park Shuttle.

The NYC system was built a century ago and operates at an astonishing level considering its for one city and is so relatively inexpensive.

https://en.m.wikipedia.org/wiki/New_York_City_Subway#:~:text=By%20annual%20ridership%2C%20the%20New,carried%201%2C793%2C073%2C000%20riders%20in%202022.