The Blackout of 1977
If the third rail goes out, the train operators are instructed to try to coast into the next station, or express trains into the next local station.
In fact in the 1977 blackout, only a few trains were stuck between stations. When the duty Supterintendent realized what was happening he had all the trains contacted by radio to stop in the next station or express trains to stop at the next local station.
The Fourth Ave Subway Summer of 1966
I was in a no power section of the Fourth Ave line on a T train (so you know how long ago that was). As we left 36th St on the express, the lights began to flicker off and on. We were already moving well, so the motorman (that's what they were called then), let the train coast after the power went off and stayed off. It looked like we would make it into Pacific St, until the signal between 9th St and Union St, was red. He stopped the train. This signal had a push button key by allowed (ah, the good old days). After seeing the stop arm go down, he released the brakes. We were on just enough downgrade to begin to move. Really s l o w l y at first.
There was a section break ahead near Union St, in fact, we could see a train in Pacific with its lights on, so it had power. Finally we reached the section break, the first car got power, then the second, by the time the third car was juiced, the motorman opened the controller to get a little more speed. We made it into Pacific from there.
2004 by Joseph D. Korman