Railway engineers need to learn how to calculate the superelevation grade of a rail, also known as its cant. The superelevation grade dictates the maximum safe speed around a curve. Usually, the outside rail is elevated relative to the inside rail, creating a banked turn. However, sometimes geography dictates that the opposite occur, which is sometimes called an adverse cant. This situation requires a much slower speed to prevent the train from derailing.
Instructions
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1
Obtain the inside and outside rail elevations from a schematic of the railway. These measurements are usually given in inches in the U.S., and in centimeters elsewhere.
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2
Subtract the height of the inside rail from the height of the outside rail.
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3
Write down the difference, which is your superelevation grade.