Which action by a train operator is considered a violation of rules?

Using the switching position on the master controller as a running position is a violation of operational rules because the master controller is designed to manage the electrical and mechanical systems of the train under specific conditions. The "switching" position typically refers to a setting for maneuvering trains at low speeds or during switching operations in yards, not for regular train operations at full speed or on main lines. Engaging that position while in a running context can result in unsafe conditions, including inadequate power supply to the train's traction motors, which could lead to loss of control or train movement stops.

Conversely, utilizing the emergency brake is a necessary safety measure in critical situations, such as preventing accidents, and is an appropriate action when warranted. Checking signal lights prior to departure is a standard procedure that ensures safe operations and proper communication among railway systems. Similarly, conducting equipment inspections is a fundamental part of pre-operation checks to ensure everything is functioning correctly and safely. Thus, these actions are in line with established safety protocols and operational guidelines.