What type of signals are classified as fixed signals according to train operation rules?

Fixed signals are established signals that remain in a consistent location and provide information to train operators about track conditions, movement authority, and operational instructions. Repeater signals fall into this category, as they serve to repeat the information provided by a primary signal to ensure that operators can see it from a distance or around obstructions.

Temporary signals, warning signals, and emergency signals, while important in train operations, are typically used in specific situations or under certain conditions rather than serving as fixed indicators. Temporary signals are often used for construction or track maintenance and are not permanent fixtures. Warning signals generally alert operators to potential hazards and are more situational than fixed, while emergency signals are activated under specific urgent circumstances. Thus, repeater signals stand out as a classic example of fixed signals as they provide continuous, reliable communication of essential operational information.