What is the main purpose of alcohol evaporators in air braking systems?

The main purpose of alcohol evaporators in air braking systems is to prevent ice formation in air brake valves. In certain conditions, especially when the air pressure within the system decreases, moisture can condense and freeze, which may lead to blockages in the brake system. This could result in less effective braking performance or even total brake failure.

Alcohol is introduced into the air brake system as it can lower the freezing point of moisture present, thereby helping to keep components like valves and hoses free of ice. By performing this essential function, alcohol evaporators play a crucial role in maintaining the overall functionality and safety of the air brake system, especially in colder climates where ice formation is more likely.

The other options may appear relevant but do not accurately address the primary function of alcohol evaporators in the context of safety and performance for air brakes.