National Research Council of Canada. NRC Centre for Surface Transportation Technology
8th International Conference on Contact Mechanics and Wear of Rail, Wheel Systems: 15th - 18th September 2009, Firenze, Italy
Through a range of increasingly featured models of wheel-rail contact, vehicles and track it is possible to model in great
detail the vehicle/track performance. But one aspect of the wheel/rail interaction that remains poorly understood and
more poorly applied in models is the traction-creepage characteristic. Most models depend on the theory of Kalker, one
that applies to “scrupulously clean surfaces”. A simple scaling factor approach to the Kalker model is available in
many of the existing dynamics codes but is poorly understood and often not used. Even in the UK, with more
experience than most countries in understanding prevailing friction conditions, consistent peak friction measurements of
0.23 +/- about 0.05 standard deviation are co-opted by the use of a 0.45 value in many experiments because the larger
value gives ”best agreement with test force measurements and observations”.
We report on a new instrument for field measurements of the traction creepage characteristic based on lateral creepage,
and then show some early measurement values and compare them with those measured by a standard Salient hand
pushed tribometer. Through dynamic modeling, the implications of the traction creepage relationship on forces, wear
and vehicle stability are explored.
Proceedings: 8th International Conference on Contact Mechanics and Wear of Rail, Wheel Systems: 15th - 18th September 2009, Firenze, Italy.