When must running lamps and tail lamps on trains in elevated service be illuminated?

Running lamps and tail lamps on trains in elevated service must be illuminated between sunrise and sunset to ensure visibility and safety. This regulation is in place to help reduce the risk of accidents and to provide clear signals to other vehicles and pedestrians. Since trains operate on set schedules that can involve various lighting conditions throughout the day, having these lamps illuminated during daylight hours is crucial for maintaining awareness of train movements.

On the contrary, while heavy fog certainly warrants enhanced visibility measures, it is not the specific regulatory requirement covered by this question. Similarly, the requirement does not limit illumination to night only or during maintenance situations, as both of these scenarios do not account for the operational needs of trains during daylight hours.