In my idle moments while waiting for a subway, I’ll often scan the tracks looking for some four-legged friends. I’ll watch as rats, ubiquitous everywhere underground in New York, scurry along the subway tracks looking for food. They dart over tracks and duck under the third rail, sometimes hopping atop it, sometimes scampering beneath. Even as the vibrations from approaching trains cause them to dart away, they avoid electrocution. It is a marvel of the subway ecosystem, but how do they do it?
Well, in this week’s FYI column in The Times, Michael Pollak has your answer:
They don’t form a grounding connection between the third rail and the track bed, transit officials said. “In order to be electrocuted you need to complete a circuit, which means you need to touch the third rail and the ground,” said John Campbell Jr., assistant chief electrical officer for New York City Transit. “It’s the same reason birds can sit on live uninsulated electric lines and not get electrocuted: there is no path for the current to flow.”
If a rat, bored with jumping, were unwise enough to reach up and touch the live part of the 600-volt third rail while keeping its other paws on the ground, it would be toast. But rats don’t do that. In most cases, either their bodies are not long enough to form a grounding connection, or their travels do not give them any reason to climb that way.
Pollak also spoke with a mammalogy expert at the American Museum of Natural History who doubts rodents’ needs to jump up on the third rail in the first place. After all, they are nimble enough to just go under. So while electrocution won’t solve the subway rat problem, perhaps, then, the MTA should just pick up the trash instead.