Which action by a train operator would NOT be a violation of the rules?

Sounding several blasts of the whistle when skipping a station is an action that aligns with operational protocols, as train operators are typically required to use their whistles to announce their approach and inform those at the station of their intent to bypass it. This practice ensures safety by alerting passengers and workers at the station, thereby minimizing the risk of accidents.

On the other hand, failing to signal before a stop, exceeding the speed limit, and neglecting to check safety equipment are violations that compromise safety and operational integrity. Each of these actions could lead to dangerous situations, so they fall outside of the acceptable practices for train operations. Thus, the choice of sounding the whistle correctly adheres to necessary communication protocols, making it the non-violation action among the options given.