Traction Overview

With rail vehicles , traction can be described as the property of the vehicle's wheels to maintain torque on rails without slipping, whether it is by accelerating or braking . This property depends on a number of factors, including the weight of the vehicle, number of powered axles , load rating , track grade and weather conditions .

Most rail vehicles are designed to function without loss of traction in dry conditions , but the rails become slippery when wet . In wet conditions, gentle applications are advised when accelerating and braking, especially on grades.

Loss of traction causes wheels to either slip or slide . Apart from notable damage to wheels , poor traction judgement can also lead to severe collision damage 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, using a sander can help increase traction. 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.