It reminds me of, and looks similar to IEE/projection displays (used on some 1970s Otis elevators, Westinghouse may even have used IEE displays), but it appears this design works differently.
This part is all assumptions (I can't find info about this type of display): It appears to use one light that is constantly on, and there is some surface with numbers cut in it that actually appears to be driven by a motor, and it moves to change the number displayed. I'm not sure if the surface is a thin wheel with the light behind it, a large wheel with the light inside of it, a belt (possibly with the light in the center of the area the belt goes around), or some kind of sliding mechanism. You can see the numbers mechanically move. They move horizontally (not sure if completely horizontally or just roughly horizontally, it is hard to tell from the video)
This indicator is not to be confused with Westinghouse "Synchrodial" indicators, a non-illuminated vertical rotating dial position indicator used as a hall indicator.
Does anyone know anything about this unusual type of position indicator? (note that I am an elevator enthusiast and not an elevator technician, but these indicators seem to be very very rare to still find and in working condition, in fact, the video was only filmed just before that elevator was modernized).
I also have found a video of a similar looking, but possibly different Westinghouse position indicator (though the one in this video doesn't seem to work correctly): https://www.youtube.com/watch?v=yFjLRkqfZOo
I assume the one in this video is an IEE/projection indicator (non-mechanical, an individual light bulb for each floor)? The fact that it didn't light up at one of the floors would also suggest this (unless that is because of a different reason). Or is it also mechanical, but the light turns off when the number changes, thus you can't see it mechanically move?