What safety feature is activated if hand pressure is removed from the master controller handle?

When hand pressure is removed from the master controller handle, the safety feature that is activated is the emergency brake application. This mechanism ensures that if the operator loses control or becomes incapacitated, the train can be safely brought to a stop. The emergency braking system is a critical safety measure designed to prevent accidents and enhance passenger safety.

In many train systems, the master controller is designed to maintain operational power and control as long as the operator is actively managing it. Removing pressure indicates that the operator is no longer engaging with the control system, prompting a rapid response to halt the train. This feature is vital for responding to unexpected situations, providing an automatic safety net.

The other choices involve features that play important roles in train operation but do not specifically trigger in response to the removal of hand pressure from the master controller. For example, while automatic throttle adjustment can manage train speed under certain conditions, it does not result from lost contact with the master controller. Power interruption to the motors would not ensure an immediate cessation of movement, and auxiliary alarms typically serve as warning signals rather than emergency stopping mechanisms.