If the trackside warning detector stops a train and no defects are found, what must the train dispatcher do?

When a trackside warning detector stops a train due to an alert and no defects are found upon investigation, the train dispatcher has a responsibility to ensure that all necessary parties are informed. Notifying the mechanical desk is crucial because this department handles the maintenance and repair of the trains, and they need to be aware of situations where trains have been stopped due to warnings.

The mechanical desk may need to perform additional checks or take preventive measures to ensure that the train is safe for its continued journey. This step is essential for maintaining safety protocols and ensuring that any potential issues are addressed promptly.

Documentation in the train log is also important, as it helps maintain a record of the incident for future reference and analysis, but the immediate step after confirming there are no defects is to inform the mechanical desk. Therefore, notifying the mechanical desk is the most appropriate action in this scenario.