What is the hand signal for 'back' described as?

• A. Swung horizontally above head
• B. Swung vertically in a circle at right angle to the track
• C. Raised and lowered vertically
• D. Swung horizontally at right angle to the track

Answer: (B)

The hand signal for 'back' is represented by swinging the arm vertically in a circle at a right angle to the track. This specific motion is distinct and recognized universally within rail operations to clearly communicate the intention for a train to reverse direction. This clarity is crucial in maintaining safety and ensuring that all crew members are on the same page regarding the actions of the train.

The other options, while they may represent different signals or actions, do not accurately convey the signal for 'back.' The horizontal movements or different vertical motions do not align with the standardized signaling practices used in rail operations, which could lead to misunderstandings and potential hazards. By using the specified circular motion, it establishes a clear and unambiguous directive that can be easily seen and recognized by train personnel.