Thus, maximum superelevation has to be limited and not all trains have the same speed.
Inserting formula (3) to formula (5), the following formula for calculating superelevation deficiency is obtained:
Superelevation deficiency is determined by the following factors (Lindahl 2001; Klauser 2005): track construction; track alignment, a type of the vehicle and running gear; axle loads and unsprung masses; the state of maintaining rolling stock.
Superelevation excess is formed if actual superelevation is higher than equilibrium superelevation.
If superelevation excess and superelevation deficiency are not equal to zero, it means that there is uncompensated lateral acceleration in the curve.
Uncompensated lateral acceleration, superelevation deficiency and superelevation excess have different regulations in different countries where they are regulated in respect of traffic intensity.
Superelevation is determined regulating uncompensated lateral acceleration in a number of countries.
It is also difficult to find out the correctness of calculating superelevation according to maximum speeds.
Superelevation Influence on Wheel/Rail Interface and Rail Wear
As noted above, different methods of calculations can be used for estimating superelevation; however, one of the negative outcomes of incorrectly calculated superelevation is rail wear (Sadeghi, Akbari 2006).
Following research on the influence of curve radius and the superelevation of the track on the stability of the vehicle system (Zeng, Wu 2004), it has been estimated that curve radius and outer rail superelevation have tremendous effects on the stability of vehicle systems.
If actual superelevation is larger than the calculated one, the wheel-set of the locomotive slides on the external rail of the curve and if superelevation is insufficient, the wheel-set slides on the internal rail.