The braking distance of a given train varies with certain conditions, such as:

• it increases as the mass or speed of the train increases.
• it increases where environmental conditions (rain, snow, volcanic ash, fallen leaves, etc.) reduce the friction between the rails and the wheels
• it increases on declines (and decreases on inclines) due to the effects of gravity
• it varies where different grades of steel are used in the rails vary the frictional qualities

A given train has a characteristic braking profile affected by its on-board features such as:

• disc brake or tread brake
• use of sand or gel to increase friction between the rails and wheels
• use of spin and slide detection software
• the frictional qualities of the wheel treads
• the type of braking system used (mechanical brakes, pneumatic brakes, electro-pneumatic brakes, dynamic brakes, etc)