What is a key responsibility of dispatchers when bridge conditions change?

A key responsibility of dispatchers when bridge conditions change is to hold all trains until a DUAL Qualified individual confirms safety. This is critical because bridges can be affected by various factors, such as severe weather, structural issues, or changing load conditions. A DUAL Qualified individual, who has the necessary expertise and qualifications, can assess the bridge's status and determine if it is safe for trains to cross.

This process ensures that safety is prioritized, preventing potential accidents that could occur if a train were to traverse an unsafe bridge. The other options, while important aspects of a dispatcher’s role, do not directly address the immediate safety concerns related to changing bridge conditions. Managing train speeds and monitoring weather conditions are proactive measures, whereas informing crews of maintenance schedules pertains more to operational logistics than immediate safety in response to a change in bridge integrity.