Son Of Leonard

You know you need to get off the island when the subways start talking to you:

Just when the train is starting, as if the cars were screeching, “There’s a place.”

. . .

Once heard, it is unmistakable: an echo of “Somewhere” that rises from the ceaseless tide of shrieks and moans in the subways.

A revival of “West Side Story” begins previews next week, but this little piece of it has been playing nonstop beneath Broadway since 2000, when new cars began rolling with an innovative propulsion system. Most of them are on the 2, 4 and 5 lines, and fresh audiences arrive daily.

. . .

The sound is a fluke. Newer trains run on alternating current, but the third rail delivers direct current; inverters chop it into frequencies that can be used by the alternating current motors, said Jeff Hakner, a professor of electrical engineering at Cooper Union. The frequencies excite the steel, he said, which — in the case of the R142 subway cars — responds by singing “Somewhere.” Inverters on other trains run at different frequencies and thus are not gifted with such a recognizable song.

The playwright Tony Kushner told New York magazine last year that it was his favorite New York noise. Riders often ask transit officials about it, and readers still write to the City section of The Times to report their discovery.