Which of the following codes indicates that a derailment has occurred?

The code that indicates a derailment has occurred is 10-75. This specific code is used within the context of transit communication to alert personnel to incidents involving train derailments, which is a critical situation requiring immediate attention and response.

Understanding the importance of communication codes in transit operations is essential because they provide concise and clear information about various incidents or emergencies. In this case, the use of 10-75 allows train operators and emergency personnel to prioritize their response strategies and ensure safety measures are implemented effectively.

The other codes listed serve different purposes, communicating other types of incidents or statuses within transit operations, but are not applicable to derailment notifications. Therefore, knowing the correct code is vital for timely and efficient responses during emergencies.