Wheelslip occurs when the tractive effort exerted by a locomotive exceeds its adhesive weight. In simpler terms, it happens when the force applied to the wheels surpasses their ability to grip the rails. Here’s how it unfolds:
- Starting Trouble: When a locomotive begins moving (especially from a stationary position), it requires significant effort. If the engineer applies too much power to the wheels (e.g., opens the regulator too far for a steam locomotive), the wheels can spin without propelling the train forward.
- Imbalance: The primary cause of wheelslip lies in the power-to-weight ratio. Ideally, locomotives should have balanced ratios for smooth acceleration. However, if a locomotive’s power vastly exceeds its weight, wheelspin occurs due to loss of traction.
- Adverse Conditions: Wheelslip is more likely with heavier trains, compromised rail surfaces (e.g., wet or icy weather), or when oil or leaves are on the track.
- Prevention: Modern locomotives are equipped with sandboxes to drop sand or Sandite on the rails for better adhesion. Diesel and electric locomotives also have electronic wheelspin detectors that reduce power if wheelspin is detected.
Maintaining the delicate balance between power and adhesion is crucial for safe and efficient rail travel.
