How far ahead must yellow flags be placed before a restriction?

Placing yellow flags ahead of a restriction serves to notify train crews of upcoming conditions that may require reduced speed or caution. The correct distance for placing these flags is 2 miles ahead of the restriction. This distance allows train operators ample time to adjust their speed and prepare for the changes ahead.

The rationale behind the 2-mile requirement is based on ensuring safety and providing sufficient notice to ensure that trains can respond accordingly. If flags were placed too close to the restriction, there would not be enough time for crews to react, which could lead to safety incidents. The chosen distance ensures that trains can operate safely and within the established limits even as they approach potentially hazardous conditions.