How is the hand signal for 'Stop' communicated?

The hand signal for 'Stop' is effectively communicated by swinging the arm at a right angle to the track. This specific gesture is standardized in signaling to ensure clarity and immediate comprehension among train operators and crew members. The positioning and movement of the arm are designed to be highly visible and distinct, allowing for quick recognition in various lighting conditions and distances.

In contrast, other methods like raising one hand above the head or using flashlight signals may have specific applications but do not specifically indicate 'Stop' in this context. Waving both arms in a circular motion could be misinterpreted or not recognized as a standard signal for stopping a train, thus further emphasizing the importance of using the correct, well-known hand signal of swinging the arm at a right angle. The adherence to these signal standards is crucial for safety and operational efficiency on the train tracks.