If you're curious how subways signaling/safety mechanisms operate, the nycsubway site[1] has a pretty good rundown on NYC's procedures, and its original languag

If you're curious how subways signaling/safety mechanisms operate, the nycsubway site[1] has a pretty good rundown on NYC's procedures, and its original language is English as well. It basically is a large ad-hoc system (+ some remote control) with lots failsafes. [1] http://www.nycsubway.org/wiki/Subway_Signals:_A_Complete_Guide http://www.nycsubway.org/wiki/Subway_Signals:_A_Complete_Gui...