What is the first step in reducing pressure in overcharged train brake systems?

In a situation where you need to reduce pressure in overcharged train brake systems, adjusting the regulating valve to the desired pressure is the appropriate first step. The regulating valve manages the system's pressure, and by adjusting it, you can ensure that the brakes function correctly without exceeding the necessary pressure limits.

Charging the system to the required pressure is a preliminary step that should already have been completed prior to the issue of overcharging. Making a full service brake pipe reduction initiates a reduction of pressure but is not a primary method for correcting an overcharge scenario, as it is intended for active brake engagement rather than pressure correction. Moving the automatic brake valve handle to RELEASE would not effectively manage overcharging because it does not directly address the need to adjust the pressure; instead, it would disengage the brakes which could still leave the system in an overcharged state if not managed properly. Therefore, adjusting the regulating valve is the key action to control and rectify the system pressure effectively.