What should be regarded as the most restrictive indication if a signal is improperly displayed or absent?

When a signal is improperly displayed or absent, it should always be treated with caution, considering safety as the top priority. The most restrictive indication it can give is considered the safest approach because it ensures that the engineer or conductor operates under the assumption that the worst-case scenario applies. In rail operations, this fallback is crucial, as assuming a less restrictive condition could lead to unsafe situations, such as collisions or derailments.

In practice, treating the signal as providing its most restrictive indication serves as a safety net while the situation is assessed. This means that if a signal is unclear or malfunctioning, the operation must proceed as if it is indicating the strictest restriction, thereby ensuring that train operations remain safe until the signal status is clarified.

This approach ensures that all personnel involved in train operations, including conductors and engineers, have the necessary caution built into their response plans, fostering a culture of safety and risk aversion in the railway environment.