In order to simulate the rolling and the
curve resistance a force element acting between the wagon and track has been created.
The principle of direct contra bending manipulation technique is the fact that we need higher energy or force to withstand resistance or the curve load in order to realign the bent spinal curve which can be obtained by two methods, namely, to decrease the
curve resistance force or to increase the force to straighten the curve.
[W.sub.j] includes grade resistance ([W.sub.j]),
curve resistance ([W.sub.r]), and tunnel resistance ([W.sub.s]).