What is superelevation in relation to rail curves?

Superelevation refers specifically to the height difference between the inside and outside rails of a curved section of track. This vertical tilt is designed to counteract the lateral forces that act on a train when it travels through a curve. By raising the outer rail, superelevation helps to balance these forces, ensuring stability and comfort for passengers while maintaining speed without excessive lateral friction or risk of derailment.

The purpose of superelevation is to help trains navigate curves more safely and efficiently. If superelevation is properly used, it allows the train to maintain higher speeds through curves while reducing the risk of wheel climb or other issues that could arise from centrifugal forces. Therefore, the correct understanding of superelevation is crucial for safe rail design and operation. The other options, while related to railway operations, do not define superelevation itself.