How long does a train order remain in effect?

A train order remains in effect until it is fulfilled, superseded, or annulled. This means that the order is active and must be complied with until the specific conditions are met: the train has successfully completed the actions outlined in the order (fulfilled), a new order has been issued that changes the original instructions (superseded), or the order has been formally retracted before the conditions have been met (annulled).

This principle ensures that train crews and dispatchers have clear and valid directives that govern operations, preventing confusion and promoting safety on the railways. The other options do not capture the full scope of how long a train order is valid and could potentially lead to operational issues or misunderstandings if taken as complete.