What must be done if communication between the two drivers of the combined train is lost?

In situations where communication between two drivers of a combined train is lost, it is critical to prioritize safety and ensure that both sections of the train can respond effectively to any potential hazards. Stopping immediately until communication is re-established is the most prudent course of action. This approach minimizes the risk of accidents that could arise from the lack of coordination between the two drivers, who rely on constant communication to manage their respective sections of the train.

The immediate stop allows for thorough checks and provides time for communication to be re-established, ensuring that both drivers can operate in alignment once again. Operating the trains at increased speed or continuing to move, even at reduced speed, introduces significant risks. It could lead to uncontrolled situations if either driver needs to respond to emergency conditions without proper communication.

Therefore, halting the trains until dialogue is resumed is not just a safety measure; it's a necessary protocol in railway operations to maintain safety and control in the face of communication failures.