[bontaq]

A modern tech stack won't help that much, there are other issues.

> Most subway services cannot significantly increase their frequencies during rush hours, except for the 1, G, J/Z, L, and M trains (the L service already is automated with CBTC).

> However, even without CBTC, the system is currently retrofitted to operate at frequencies of up to 60 trains per hour (tph) on the IND Queens Boulevard Line (30 tph on each of the local and express pairs of tracks made possible by the Jamaica–179th Street terminal, which has four sidings past the terminal for each set of tracks) and 33 tph on the IRT Flushing Line.

https://en.wikipedia.org/wiki/Signaling_of_the_New_York_City...