These are basically Air brakes which only applies to the locomotive and not the entire train. These are used to hold the train when parked on non-gradient surface. The air from the reservoir is pumped to the brake cylinders located one on each wheel of the locomotive only, which applies the brakes on the wheels.

Yes, electric trains in 2026 utilize air brakes as their primary fail-safe mechanical braking system, but they work in tandem with advanced regenerative braking. The air brake system on an electric train operates on the same "Westinghouse" principle as freight trains: compressed air is used to hold the brake shoes off the wheels, so if a hose breaks and air pressure is lost, the brakes automatically apply to stop the train safely. In an electric locomotive, the air compressor is powered by its own electric motor. However, for everyday slowing, electric trains use their traction motors as generators to create "dynamic" or "regenerative" braking, which converts the train's kinetic energy back into electricity to be fed into the overhead lines or battery banks. The mechanical air brakes are typically only used for the final few miles per hour of a stop, for emergency halting, or for "holding" the train stationary at a station platform or on a steep grade.