What is the purpose of the emergency airline in a trailer?

The emergency airline in a trailer is designed to control the air supply to the trailer's emergency brakes. It is a crucial component of the air brake system on combination vehicles, ensuring that emergency braking functions are activated properly when needed. This airline works in conjunction with the service airline, and it serves a vital role in maintaining safety in case of air loss or failure in the main supply line.

Understanding the function of the emergency airline is essential for drivers because it ensures that in the event of a malfunction, the vehicle can still safely come to a stop. The other options do not accurately describe the purpose of the emergency airline: the connection to the air tanks is part of the system but not its primary function, the electrical system is managed separately, and temperature regulation pertains to cargo systems that do not involve the air brake lines.