What must the Dispatcher do following a report of a failure of Speed Control and/or Automatic Train Stop?

The correct choice emphasizes the necessity for communication between dispatching districts, divisions, or railroads in the event of a failure in Speed Control and/or Automatic Train Stop systems. When such critical systems fail, the safety of train operations can be compromised, making it essential for the Dispatcher to inform the next level of dispatching—this could involve notifying supervisors or connecting railroads of the situation to ensure safety measures are implemented across the network.

This action is critical because coordination between different operational areas enables a comprehensive response to the failure. It allows for the assessment of potential risks and helps in managing train movements within the affected regions, as well as adjusting schedules and operations accordingly.

The other choices, although related to an emergency response, do not address the immediate need for communication with connecting districts or railroads, which is vital for proper operational management in response to a serious system failure. Providing a written report or canceling all outgoing trains might be necessary steps later on, but they do not substitute the immediate need to alert and coordinate with other dispatch areas involved in train operations. Communicating with emergency services could be necessary depending on the severity of the situation, but prior notification between dispatching entities is often the first critical step to ensure ongoing operational safety.