Have you ever played with toy train sets and seen the little lever on the tracks that can make the train suddenly stop? Well, real trains have something similar called an emergency brake.
Just like in a car, a train has brakes that can be used to slow it down or bring it to a stop. But when something really dangerous happens, like an obstacle on the tracks or the train is going too fast, the conductor can pull a special lever that activates the emergency brake.
When the emergency brake is pulled, it tells the brakes to start working really hard, and the train will come to a quick stop. This system is very important because in an emergency, it can help prevent accidents and keep everyone safe.