What is considered a heavy grade for a train with more than 4000 trailing tons?

The definition of a heavy grade for a train with more than 4000 trailing tons is characterized as an average grade of one percent or greater over three continuous miles. This criterion is important for safe train operations, as longer stretches of steady grade can significantly impact a train's performance, braking distance, and overall stability. A one percent grade over three continuous miles provides a clear reference for engineers to assess the operational challenges posed by terrain.

In railway operations, understanding the impact of grade on train handling and performance is crucial, especially for heavier trains. This definition ensures that train crews are alerted to possible increased demands on traction and braking systems when operating in such conditions. Knowing the parameters of what constitutes a heavy grade allows for better planning and adherence to safety protocols when traversing challenging sections of track.