What Would Happen If You Pulled The Emergency Brake On A Train
This is What Would Happen If, a close examination of mundane hypothetical situations. Each week, we look at something that you could do but probably never would, and take it to its logical endpoint. This week: What would happen if you pulled the train's emergency brake?
There's one thing you should know about the emergency brake. You should not pull the emergency brake.
As far as mundane counter-intuitive concepts goes, the emergency brake is up there. Where else in life do you have such easy access to something capable of bringing hundreds of tons of metal and flesh to a screeching halt? Buses do not have them. Airplanes do not have them. But trains, well, the potential for vast inconvenience and possible destruction hangs in every car.
Nowhere is the paradoxical nature and forbidden fruitness of the emergency brake more apparent than in the New York City subway. Next to the emergency brake sits a list of instructions of what to do in the case of emergency. On one point, the MTA is very clear: In the case of emergency, you should not pull the emergency cord.
As it turns out, halting a speeding multi-ton hunk of steel has its complications. Trains like those used by the MTA and other mass transit systems around the globe use air brakes. Unlike our familiar understanding of braking systems derived from cars — where an increase in pressure translates into an increase of pressure on the brakes — air brakes on a train run in the opposite way. By default, the air brake system is closed. When a train operator wants to apply the brakes, they reduce air pressure in the braking system, which then opens the brakes. The logic at work here is that if there's a pressure failure in the braking system, the brakes will automatically engage — reducing the likelihood that a train's brakes would "go out."
What happens when you pull an emergency brake is that you are inducing this rapid loss of pressure. You pull the brake, air is vented from the train's brake pipe, and the brakes slam shut. As you can guess, this will cause the train to stop. If the train is moving at speed, that stop will be violent. As recently as this year, one New York City subway train derailed after an emergency brake was pulled. Other systems, like London's Underground, have a passenger alarm where a train operator has the option to override the brake.
In either case, it's strongly recommended that you do not pull the brake in the event of an emergency if only for the fact that it's easier for help to arrive if you're at a station, and not, say, in the middle of a dark tunnel underneath a river. It might sound obvious, but a railroad is not a road. Authorities can't just drive up to you wherever you're stopped in the system.
Similarly, a stopped train can't just be started up again. Police investigations and evacuations procedures aside, a New York Times report from 2010 cited that it takes somewhere between 5-10 minutes to reset the train's brakes. This, of course, does not take into account the time it takes a maintenance crew to get to the train, assess any potential damage and get the all-clear from a dispatcher. In other words, pulling the brake will most likely leave you stranded inside a train for the better part of an hour, if not longer.
There are, of course, consequences for pulling the emergency brake unnecessarily. This obviously depends on where you are in the world when you decide to pull the big reg cord, but according to the MTA's own Rules of Conduct, at the very least, you'll get slapped with a $100 fine. If you pulling the brake leads to further consequences — like damage to the train, or injury (and potentially death) to your fellow passengers, well, you're probably looking at further criminal charges.
Given all this, it might seem like pulling the emergency brake is almost always more trouble than it's worth. Despite rider confusion brought up in the New York Times' 2010 report, the MTA is clear when activating the brake is warranted: "Use the emergency brake cord only when the motion of the subway presents an imminent danger to life and limb." In other words, if the train moving is going to lead to something bad happening, then you should use the emergency brake to stop it. The ethics of such a thing are slightly murky, but if you enjoy strangers on the internet trying to work through it then this Stackexchange thread on emergency brake usage is a delight.
A likely scenario is thus: You pull the cord. The train stops. Everyone aboard is stuck, and thus gets upset. Maybe they rat you out. Maybe they don't. Service is restored with delays. This causes more people to become upset. Life goes on. In that 2010 Times report, the MTA estimated that the emergency brake is pulled some 1,000 times per year. The trains must keep running. You know this.
