What characterizes a heavy grade in train operations?

A heavy grade in train operations is characterized by a slope of at least 1% sustained over a distance of 3 miles or more. This definition reflects the significant impact such a gradient can have on train handling and braking performance. On a heavy grade, trains encounter a considerable increase in the challenges associated with maintaining speed and ensuring safety, particularly concerning braking distances and the potential for losing control of the train.

Understanding this definition is essential for train crews as it influences how they manage speed, braking, and overall train handling while traversing inclines. The length of the grade—as specified—also plays a critical role in how a train will behave under various operating conditions, making the knowledge of heavy grades vital for effective train operations.