What is essential for ensuring safety on tracks that are rusty?

Ensuring safety on tracks that are rusty is critical, and permitting only one train at a time in a block is an essential measure to reduce risks. Rusty tracks can affect grip and traction, potentially leading to increased stopping distances and unstable train handling. Allowing just one train at a time minimizes the chances of collisions and allows for better control of train movement, reducing the likelihood of accidents or derailments.

This practice ensures a safe operating environment, allowing for closer monitoring of track conditions and the opportunity to respond quickly to any issues that may arise during a train's journey. By limiting train movements, dispatchers can manage the risks associated with degraded track conditions effectively.

Other options, such as allowing multiple trains or maintaining maximum speeds, would increase the possibility of accidents in such conditions, and asserting no special requirements would overlook necessary safety measures. Therefore, restricting operations to one train per block is a prudent approach to maintaining safety on compromised track infrastructure.