What is required of the operator when a signal exhibits YELLOW OVER YELLOW OVER YELLOW?

When a signal displays YELLOW OVER YELLOW OVER YELLOW, the indication is for the operator to proceed with extreme caution and at a reduced speed. This signal typically suggests that there may be a potential hazard or an upcoming change in conditions that the operator needs to be aware of. It is a warning to prepare for the possibility of further signals or obstacles ahead.

Operating with extreme caution emphasizes the need to remain vigilant while navigating through areas where visibility might be compromised or where unexpected situations could arise. Reduced speed allows the operator to maintain control of the vehicle while also being prepared to respond to any upcoming changes in signal indications or track conditions. This aspect of operational safety is critical in ensuring the well-being of both the train crew and any surrounding personnel or equipment.