Traction Overview

In the context of trains, traction can be described as a property of wheels to torque over rails without slipping. It depends on a number of factors, including the weight of a vehicle, number of powered axles, torque, track grade and weather conditions.

Most vehicles are designed to function without loss of traction in dry conditions, but the rails become slippery when it’s raining. In that case, gentle applications are advised when accelerating and braking, especially on grades.

Loss of traction causes wheels to either slip or slide. Apart from the imminent wear, poor judgment can lead to severe collisions and derailments.

Most cabs are equipped with an indicator for traction loss, commonly a blinking warning light and sometimes with a buzzer too.

In most situations, to help increase traction, the driver can use an onboard sander. There are cases where adding a slug to the train can help too.

Vehicles that can carry significant amounts of fuel or cargo onboard, such as steam locomotives, may experience drastic differences in traction depending on their load.

See also: Sander, Wheelslip, Wheelslide, Slug, Weather