Northeast Operating Rules Advisory Committee (NORAC) Practice Test

When a train receives a Form D line 13, this indicates that the train must be prepared to stop unless a specific signal indicates otherwise, in this case, an Approach Normal. The instruction to prepare to stop emphasizes the need for caution and attentiveness to signal indications.

This means the crew should be vigilant and ready to halt the train if the signal ahead does not display an Approach Normal indication. This procedure is crucial for ensuring safety, as it allows the train to adequately respond to any potential hazards or conditions ahead that may require a stop. The intent is to equip the train crew with the necessary information to operate safely in possibly unclear or changing signal conditions.