What safety feature is used in air brake systems to prevent overheating?

The correct answer highlights the role of spring brakes in preventing overheating within air brake systems. Spring brakes are a critical component of air brake systems that provide a failsafe in the event of a loss of air pressure in the system. They operate by utilizing large coil springs that, when compressed by air pressure, are held in place. If the air pressure drops significantly, these springs are designed to apply the brakes automatically.

This mechanism is essential because, in the absence of sufficient air pressure, the continued operation of the vehicle can lead to situations where the brakes could overheat, especially in prolonged or heavy braking scenarios. When spring brakes engage, they ensure that the vehicle comes to a stop safely, thus preventing further friction and potential overheating of the brake components.

The other options do not effectively address the issue of overheating in the same way. For example, heat resistant brake fluid is not typically a feature associated with air brakes, and while cooling ducts could theoretically aid in thermal management, they are not standard in air brake systems. Electronic monitoring systems may be implemented for various functions but do not directly contribute to preventing overheating in the same manner as spring brakes do.