What is the purpose of Rule 502?

The purpose of Rule 502 is to prohibit block entry without dispatcher permission. This rule is crucial for maintaining safety and operational integrity within railway systems, particularly where signaling may not be in place or when dealing with controlled environments. By requiring explicit permission from a dispatcher before entering a block, the rule ensures that trains operating within a particular segment of the railway are adequately monitored and controlled. This approach significantly helps in preventing collisions and ensuring that all movements are accounted for, thus contributing to the overall safety of rail operations.

While other options may touch upon different operational aspects, they do not align with the core intent of Rule 502, which emphasizes the necessity of dispatcher authorization before a train can proceed into a block.