What must lone workers do when using individual train detection before fouling the track?

When lone workers are using individual train detection before closely approaching or fouling the track, it is essential for them to complete a statement of on-track safety. This action is crucial as it formalizes the process of ensuring that they have taken the necessary steps to work safely without the immediate risk of train movements in their work zone.

By completing this statement, the worker acknowledges their understanding of the safety requirements and confirms that they are taking appropriate precautions. This documentation serves as a record that the individual has followed the established safety protocols, reinforcing the commitment to safe work practices on or near the tracks.

The other options do not fulfill the critical requirement of establishing on-track safety in the same manner. While notifying the work crew, checking signals, or obtaining permission from a supervisor might be relevant procedures in certain contexts, none of them specifically address the need for personal accountability and safety documentation that the statement of on-track safety provides. This statement acts as a protective measure for the lone worker, ensuring that they can proceed with their tasks with as little risk as possible.