I want to find a timetable display for trains, where the letters flip
around to show the new time and destination of the next trains.  This
kind of machine used to be in Grand Central Terminal, and Penn
Station, New York, until digital displays replaced the automatic
flipping kind. Any idea where the Penn station or Grand Central ones
went, or if any one still makes them or refurbishes them...thanks

As far as I can tell, the Grand Central timetable display flips. 
There are computer displays elsewhere in the terminal, but the main
timetable on the South wall is the old-fashioned kind.

Alanna-ga

In Britain they are sometimes called 'solari' boards after the Italian
manufacturer Solari et Udine. In Britain the flaps usually carry an
entire placename, so only the pre-printed text (in various
permutations) can be displayed, but it is possible to use individual
flappers for individual letters, so text messages can be shown.

http://www.solari.it/solari/en/prodotti/display/ecf/

http://www.solari.it/solari/en/prodotti/display/ecf/photoalbum
photo gallery of flap boards

Owain