hätäjarru

Hätäjarru, often translated as emergency brake, is a safety feature found in various forms of transportation, primarily trains and buses, but also present in some other vehicles and industrial machinery. Its primary purpose is to allow for rapid deceleration or complete stopping of the vehicle in situations where the normal braking system may be insufficient or has failed.

In trains, the hätäjarru typically consists of a lever or button accessible to passengers and crew. When activated, it directly engages the braking system, often by applying pressure to the wheels through a mechanical linkage or by releasing compressed air that forces brake shoes against the wheels. This action is designed to be powerful and immediate, intended for genuine emergencies where a collision or other severe hazard is imminent. The use of the hätäjarru is generally discouraged for non-emergency situations due to the potential for passenger discomfort, damage to the train or track, and disruption to schedules.

In buses, the hätäjarru is often a cord or lever that passengers can pull or push. It serves a similar function of initiating an emergency stop, though its implementation and power can vary. Modern buses may also incorporate advanced electronic systems that integrate with the hätäjarru function.

Industrial equipment, such as elevators or escalators, also feature emergency braking mechanisms to prevent accidents. The design and operation of a hätäjarru are always centered on safety, providing a last resort to stop a moving object quickly when normal control is lost.