Nonsense! Most of the cars are new. I'm not sure if the cars were even air conditioned back in '73. Now they all are. Many cars have electronic maps displaying information about the upcoming rout of the train. Many stations have electronic signs indication the number of minutes until the next several trains will arrive. One of the lines I take (from Times Sq to 2nd Av and 72nd Street) is completely new as are some lines in Queens I might have taken when I lived on Long Island.
Last week I was in a station I used to use all the time before 1973, but I probably haven't used it at all for the past 40 years. This is the station at 53rd and Lex. It's a deep station and I remember it well with the escalators in tubes that sane people take to get up or down. Nothing about the upper level of the station is the same. It's clean and brightly lit now. The tube escalators are still there but now the insides of the tubes are covered with decorations and ads. The train level is remarkably the same as it was, which sort of surprised me as many of the stations have been retiled, sometimes with artwork, in an attempt to make them more pleasant.
The other thing that's new is that every line, in Manhattan at least, periodically seems to have notices posted that they will not be running at night presumably for track repairs. I don't remember this ever occurring back in '73.
And the penny gum machines are gone now.
ML/NJ
Well I took the 7 train from Queens to Manhattan last month and it looked exactly the same,maybe they are new but I sure as hell didn’t see anything different.