Train handling and traction/braking technique
What this domain tests
The exam tests practical control: applying power smoothly, managing adhesion, using dynamic or regenerative braking, and knowing when to use the air brake. Stopping distance depends on speed, gradient, adhesion, brake performance, and reaction time. Questions often describe weather or railhead conditions and ask for the correct technique.
Core technique
- Power application: smooth, progressive steps reduce wheelslip and coupler forces.
- Braking: make an initial light application to test adhesion, then increase as needed.
- Low adhesion: brake earlier, use sanding where available, avoid sudden large brake steps, and be ready for wheelslide.
- Dynamic/regenerative braking: useful for controlling speed on gradients, but it can fade or be unavailable; know the fallback.
- Brake fade: overheating can reduce braking effect; manage long descending grades with proper brake strategy.
Worked example
You are stopping at a station on wet leaves at 40 mph. What do you do?
Reasoning: low adhesion means the normal braking point is too late. Brake earlier and lighter, test adhesion with a small application, use sanding if fitted, and avoid a single heavy brake step that could cause wheelslide. If the wheels slide, release and reapply rather than holding the brake. Be prepared to stop short and report the railhead condition.
Traps that cost marks
- Using dry-rail stopping distances in wet or leaf-fall conditions.
- Over-relying on dynamic braking until it fades on a long descent.
- Making a heavy brake application first and causing wheelslide.
- Forgetting gradient effects on stopping distance.