Alleypet, I recall the old passageway under 33rd street that I believe went thru a slice of Gimbel's basement...I think it was closed when the homeless made it unusable...
I am not familiar with a passage under Sixth Avenue that extended to 42nd Street....could you elaborate a little on that one?
http://secondavenuesagas.com/2010/04/15/twenty-years-later-subway-passageways-lost-to-time/
This passageway dates from the construction of the IND, and it originally opened, as the Municipal Arts Society recounted, in 1940. A piece from the May 4 New Yorker that year introduced the city to the tunnel as a work in progress:
It’s a passageway running from Thirty-fifth Street to Fortieth, connecting with both the Thirty-fourth and Forty-second Street stations. The idea is that it will relieve congestion at these points by distributing passengers over a greater area. If you add the length of the station platforms to the length of the underpass, you have something impressive – a stretch of more than nine blocks, from Thirty-third Street to north of Forty-second. There will be a catch to using this as a summer promenade, however. There will be turnstiles at the ends of both station platforms, so it will cost ten cents to make the entire distance. The arrangement should nevertheless be a boon to adventurous strollers in the summer of 1941…At the south end, once you’re through the turnstile, you will be able to wander on indefinitely underground: through territory of the BMT, the Hudson & Manhattan terminal, Saks-Thirty-fourth Street, Gimbel’s, the Pennsylvania Station – a whole world in itself.
For years, the passageway served as a short cut away from the crowds on 6th Ave., but as the subway system fell into ruin, so too did these less-than-secure areas underground. Eventually by the 1980s and early 1990s, homeless people outnumbered commuters, and long, dark passageways were hallmarks of the unsafe subways. Junkies and pushers sprung up in area that bred graffiti and saw nary a cop – or station agent – patrolling the grounds.
Here is a video