Why is notification of the route request necessary?

Notification of the route request is essential primarily because it allows train operators to be alerted about the specific route that a train intends to take. This alert mechanism is crucial in maintaining effective communication and coordination among train crews, control centers, and other personnel involved in train operations. When operators are informed of route requests, they can prepare for changes, manage timetables effectively, and ensure that trains can operate smoothly without conflicts on the tracks.

The other options, while they may touch on aspects related to safe and efficient train operations, do not focus on the direct necessity of alerting train operators about route requests. Ensuring passenger safety, accurately recording train schedules, and improving signal lighting are all important, but they stem from the foundational requirement of proper communication regarding route requests to facilitate safe and efficient train movement.