False gradient is a term that describes what?

False gradient refers to the condition in which the air brake system is not fully charged, which can affect the operation and effectiveness of the braking system. When the brake system is less than fully charged, the pressure may not be sufficient to apply the brakes effectively, leading to a situation where the gradient or slope may not be accurately represented in terms of braking power.

This situation can create an illusion of the slope or gradient being steeper than it actually is because the brakes may not engage properly due to insufficient pressure. Understanding this concept is crucial for train handling, as it affects how a train responds to different gradients, particularly when descending or ascending.

The other options describe different types of gradients but do not relate to the air brake charging system. Recognizing the significance of a fully charged brake system is essential for safe and effective train operation, especially in varying terrain conditions.