Railroad signals are visual indicators used to communicate important information to train operators. They help ensure safe train operations by conveying messages about track conditions, speed limits, and the presence of other trains. Signals can be found along the tracks and are typically illuminated or use colored lights to indicate different statuses. There are various types of railroad signals, including stop signals, which instruct trains to halt, and caution signals, which advise operators to proceed with caution. These signals are crucial for maintaining safety and efficiency in the railroad system, preventing accidents and ensuring smooth train movements.