What is the proper sequence for opening the brake pipe angle cock when adding helpers?

The proper sequence for opening the brake pipe angle cock when adding helpers is to first open it on the locomotive and then on the car. This method ensures that the brake system is pressurized in a controlled manner, allowing for the gradual buildup of air pressure and reducing the risk of air surges that can lead to unintended braking actions or disruptions in air flow.

When the angle cock on the locomotive is opened first, it allows the main reservoir to supply air to the entire brake system, enabling an efficient build-up of pressure throughout the train. Following this, opening the angle cock on the car allows the airflow to adapt to the increased pressure gradually, rather than abruptly, ensuring smoother operation and a consistent communication of air throughout the train’s air brake system.

By adhering to this sequence, train crews can ensure that the helpers are integrated safely and effectively into the train's braking system, optimizing safety and performance while minimizing potential complications associated with air pressure imbalances.