Which reservoirs are charged when the train brake system is initially charged?

When the train brake system is initially charged, the emergency and auxiliary reservoirs are the primary components that receive air from the compressor. The purpose of these reservoirs is to store air at a pressure that can be used to apply the brakes. The emergency reservoir provides a backup source of air that can quickly be utilized in case of a sudden loss of pressure, ensuring that the train can stop safely. Meanwhile, the auxiliary reservoir is charged with air that is utilized for the regular operation of the train’s brakes, supplying the necessary air pressure for the brake application once the brakes are engaged by the crew.

Charging these reservoirs is crucial because it establishes the baseline pressure required for effective and safe brake operation, ensuring that there is enough air available for both normal and emergency braking situations. The other components listed, such as the brake pipe and control valves, play roles in the brake system’s overall function but are not the main reservoirs that store air during the initial charging process.