NYC’s subway signal system: How it keeps trains from colliding and other things you probably never knew

Like Harry Potter’s Hogwarts, the New York City Transit Signal Training School is hidden away from mere mortal commuters — only an out-of-place working traffic signal marks its beige entrance at the 14th Street and Eighth Avenue subway station.

It is here that the electrical wizards who maintain the critical signal system are trained. That system, which helps operators to detect where subway trains are over the 659 miles of track in the transit network, includes 12,000 signals, 2,600 track switches and 300,000 signal relays. Over an 18-month course, trainees learn how to troubleshoot and replace relays wires, levers and other equipment, much of which dates back to the Great Depression.

Most trainees have some kind of background in electrical engineering or an interest in electrical mechanics. They are the men and women who, if it weren’t for them, trains might crash into each other throughout the city’s subway network.

On a recent tour of the school, amNewYork heard from top officials about how the signal system works and how critical it is to keeping straphangers safe. Here’s what we learned.