Under what condition may the PTC system be cut out or disabled?

The ability to cut out or disable the Positive Train Control (PTC) system is strictly regulated for safety reasons. It is only permissible when there is proper authorization, which ensures that such actions are taken with oversight and in accordance with established rules. This minimizes the risk associated with disabling a safety-critical system like PTC, which is designed to prevent collisions and derailments.

Authorization typically comes from relevant railroad authorities, ensuring that any decision made is in line with operational standards and regulatory requirements. This ensures that all personnel involved are aware of the potential risks and the protocols in place to manage them appropriately. The other conditions, such as weather events or decisions made at the train dispatcher's discretion, do not align with the stringent safety protocols that govern the use of PTC systems, as they may lead to inadvertent mistakes without proper oversight. Therefore, the need for authorization ensures operational safety and compliance with regulations.