Effect of Adhesion Limits
See also: Traction (engineering)Adhesion is caused by friction, with maximum tangential force produced by a driving wheel before slipping given by:
- Fmax= coefficient of friction x Weight on wheel
Usually the force needed to start sliding is greater than that needed to continue sliding. The former is concerned with static friction, referred colloquially to as 'stiction', or 'limiting friction', whilst the latter is called 'sliding friction'.
For steel on steel, the coefficient of friction can be as high as 0.78, under the best of conditions (= utopic laboratory condition, on railway realty: 0.35 -0.5 ), whilst under extreme conditions it can fall to as low as 0.05. Thus a 100 tonne locomotive could have a tractive effort of 350 kilonewton, under the ideal conditions (assuming sufficient force can be produced by the engine), falling to a 50 kilonewton under the worst conditions.
Read more about this topic: Rail Adhesion
Famous quotes containing the words effect of, effect and/or limits:
“The effect of a good government is to make life more valuable; of a bad one, to make it less valuable.”
—Henry David Thoreau (1817–1862)
“Mix salt and sand, and it shall puzzle the wisest of men, with his mere natural appliances, to separate all the grains of sand from all the grains of salt; but a shower of rain will effect the same object in ten minutes.”
—Thomas Henry Huxley (1825–95)
“This teaching is not practical in the sense in which the New Testament is. It is not always sound sense in practice. The Brahman never proposes courageously to assault evil, but patiently to starve it out. His active faculties are paralyzed by the idea of caste, of impassable limits of destiny and the tyranny of time.”
—Henry David Thoreau (1817–1862)