What is a requirement when handling cars over a hump?

When handling cars over a hump, it is essential to ensure that the cars are released in cuts of two or less. This practice is important for maintaining control over the movement of the cars as they descend the slope and to prevent collisions or derailments. Releasing larger cuts of cars can lead to increased speed, making it difficult to control the flow and positioning of the cars once they are released.

By limiting the release to two cars at a time, crews can better monitor the movements and ensure that the cars are spaced appropriately. This controlled approach reduces the risk of accidents and enables more precise handling of the cars as they travel along the track. Additionally, this methodology enhances safety measures in the rail yard, as it allows for a focus on the dynamics of the individual cars being released.

Other potential practices, such as handling complete or solid blocks, would not provide the necessary level of control and could lead to safety issues if the momentum is not managed properly. The approach of not releasing cars at all is impractical for operations that require the movement of freight and effectively utilizes the hump yard's design.