What is the first step when adding helpers to the rear of a train?

The first step when adding helpers to the rear of a train is to make a 20 psi brake pipe reduction. This action is crucial because it allows for the proper operation of the brake system when additional locomotives are introduced. Making this reduction establishes a clear communication between the main train and the helpers, enabling the brake systems to integrate effectively.

By creating this initial pressure drop, the air brake system can respond appropriately as the helpers are coupled, ensuring that all components work seamlessly together. This step is vital for maintaining control and safety when modifying the train configuration by adding locomotives.

In contrast, simply releasing the automatic brake valve or coupling the brake pipe hoses without first creating the necessary pressure reduction may lead to confusion or inefficiency in braking operations, compromising the safety and reliability of the train. Opening the brake pipe angle cock is also important, but it typically occurs after the initial brake pipe reduction to ensure proper air flow when the helpers are coupled.