Superelevation (Track Cant) Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 28, 2026Superelevation (Track Cant) Calculator
Designing or evaluating a railway curve? This calculator estimates the superelevation - the amount the outer rail is raised - needed for a comfortable, safe ride at a given design speed.
Superelevation (mm) = (11.8 x Speed(km/h)┬▓) / Curve Radius(m)
Example
120 km/h train speed through a 1,000m radius curve:
Superelevation = (11.8 x 120┬▓) / 1,000 = ~170 mm
Why Curves Need Banking
Superelevation (also called "cant") counteracts the centrifugal force experienced by a train traveling through a curve - without it, that force would push passengers, cargo, and the train itself toward the outer rail, causing discomfort and extra wear.
The Tradeoff Between Speed and Curve Radius
Since superelevation scales with the square of speed but only linearly with curve radius, doubling design speed requires roughly quadrupling the curve radius to keep the same superelevation - this relationship is exactly why high-speed rail lines require much gentler curves than conventional railways.