A permanent way or track should provide a comfortable and safe ride at the maximum permissible speed with minimum maintenance cost. To achieve these objectives, a sound permanent way should have the following characteristics.
(a) The gauge should be correct and uniform.
(b) The rails should have perfect cross levels. In curves, the outer rail should have a proper superelevation to take into account the centrifugal force.
(c) The alignment should be straight and free of kinks. In the case of curves, a proper transition should be provided between the straight track and the curve.
(d) The gradient should be uniform and as gentle as possible. The change of gradient should be followed by a proper vertical curve to provide a smooth ride.
(e) The track should be resilient and elastic in order to absorb the shocks and vibrations of running trains.
(f) The track should have a good drainage system so that the stability of the track is not affected by waterlogging.
(g) The track should have good lateral strength so that it can maintain its stability despite variations in temperature and other such factors.
(h) There should be provisions for easy replacement and renewal of the various track components.
(i) The track should have such a structure that not only is its initial cost low, but also its maintenance cost is minimum.