What position should the ATC Bypass switch be in when leaving the cab?

The correct position for the ATC Bypass switch when leaving the cab should indeed be in the ATC position. This setting ensures that the Automatic Train Control (ATC) system is active and monitoring train operations. By keeping the ATC engaged, it provides an additional layer of safety, preventing unauthorized movement of the train and ensuring that all safety protocols are adhered to while the train is unattended.

When the ATC is active, it enables the system to automatically control the speed and operations of the train, which protects both the equipment and personnel. This is especially crucial in areas where humans might interact with the train or in situations where an unattended train could become a hazard.

In contrast, other positions such as MCS, READY, or OFF may not provide the necessary safety assurances required when leaving the cab, potentially leading to unsafe situations if the train is inadvertently allowed to move without proper control. Thus, maintaining the ATC in the active position is paramount for safety and operational integrity.