What does the term "blocking" refer to in rail yard switching?

The term "blocking" in rail yard switching refers to the practice of arranging cars in a specific order based on their destination or cargo type. This is a crucial step in rail yard operations, as it allows for more efficient movement and handling of railcars. By grouping cars that are destined for the same location or that have similar cargo types, crews can minimize the amount of switching required during the departure process, thereby saving time and reducing labor costs.

In contrast, the other options do not accurately represent the concept of blocking. Preventing cars from moving relates more to securing cars or controlling movements rather than organizing them by destination. Disconnecting cars from the train is a mechanical operation that does not involve arranging cars for efficient transport. Loading cargo into the train is a separate operational activity that focuses on preparing the train for travel rather than the organizational strategy of blocking. Understanding blocking is essential for effective rail yard management and operational efficiency.