E.g. Paris steadily runs a train every couple minutes on many lines with no problems, and we could too after deploying switching technology improvements.
And the only pedestrian sidewalk I've ever seen at gridlocked capacity is Rockefeller center in Christmastime.
Also, merging LIRR and NJT and through-running RER style is so obvious yet never brought up. Penn is not intended to be a terminal and it shows.
http://www.streetsblog.org/2016/07/01/the-new-york-of-2016-n...
The subway problem could be partially solved with true dedicated lanes for buses/trams and offboard fare payment. It's not hard, these are both incredibly common in Europe.
I think more are planned.
We have a 24/367 Apple Store, 7 stores in Manhattan :-)