Dave Colon

The western extension of the Second Avenue Subway has a $7.7-billion price tag that calls into question the very logic of building it at all — but advocates and researchers say the train is a good idea that could cost a lot less with some minor alterations.

The same billion-dollar outlay that Mayor Mamdani hopes to allocate for fare-free buses should be spent instead on rewriting the subway map.

The president blocked funds for the Second Avenue Subway during the government shutdown in October — and the MTA has still not received the money, sources said.