I took those trains for a decade and the math doesnt add up. The capacity of the carts and speed they operate through the tunnel suggests less than a million at most.
[0]:https://www.mta.info/agency/new-york-city-transit/subway-bus...
[1]: https://content.tfl.gov.uk/travel-in-london-2025-consolidate...
[2]: https://www.mtr.com.hk/archive/corporate/en/investor/annual2...