For a mobile unit, which identifier is required when transmitting?

When transmitting from a mobile unit, it is essential to include the name or initials of the railroad along with the train identification. This requirement helps ensure clear communication and accurate identification over radio and other communication systems used in rail operations. Including the railroad's name or initials and the train identification allows dispatchers and other personnel to quickly and precisely identify the unit involved in the communication. This practice enhances safety and efficiency by minimizing confusion and ensuring that messages are directed to the appropriate parties.

The other options do not meet the necessary identification standards laid out in the operating rules. Personal names are not used for operational clarity, station names can vary and might not provide enough context, and random military codes do not relate to railroad operations, making them unsuitable for effective communication.