Super-elevation or cant Super-elevation or cant (Ca) is the height difference between the outside and the inner rail in a curve. It is provided by gradually raising the outer rail above the level of the inner rail. The inner rail is taken as the reference rail and is normally maintained at its original level. The inner rail is also known as a gradient rail. The main functions of the cant are as follows.
(a) To ensure a better distribution of the load on both rails
(b) To reduce wear on rails and rolling stock
© To neutralize the effect of lateral forces
(d) Provide passenger comfort
Equilibrium velocity When the speed of a vehicle negotiating a curved path is such that the resulting force of vehicle weight and radial acceleration is perpendicular to the plane of the rails, the vehicle is not subject to any unbalanced radial acceleration and is said Be in balance. This particular velocity is called the equilibrium velocity. The velocity of equilibrium, as such, is the rate at which the effect of the centrifugal force is completely balanced with the provided canton.
Maximum permissible speed This is the highest speed allowed for a train on a curve, taking into account the radius of curvature, actual fault, bullet depletion, excess bullet and the duration of the transition. At crossings where the maximum permissible speed is less than the maximum sectional speed of the section of the line, the permanent speed restriction becomes necessary.
Chant Deficiency Chant deficiency (Cd) occurs when a train travels around a curve at a speed greater than the equilibrium velocity. It is the difference between the theoretical limit required for such high speeds and the actual limit provided.
Cant excess Excess Cant (Ce) occurs when a train travels around a curve at a velocity less than the equilibrium velocity. It is the difference between the actual song provided and the theoretical song required for such a low speed.
Slope gradient deficiency of cant. And cant. These indicate cant increase or decrease or cant deficiency. In a given duration of transition. A gradient of 1 in 1000 means that a bite or a 1 mm thick deficiency is reached or missed per 1000 mm transition length.
Rate of change of cant deficiency. The cant. This is the rate at which cant deficiency. Increases when going through the transition curve, for example, a rate of 35 mm per second means that a vehicle will experience a change in cant or a cant deficiency. 35 mm in each second of travel during the transition when traveling at the maximum speed allowed.