Most people assume a train should be perfectly balanced on a curve—tilted just right, riding equally on both rails. But that only works for one train, at one speed. On real railways, things aren’t that simple. Enter cant deficiency.

Every train, whether carrying passengers or freight, is guided by a surprisingly small area of contact: the wheel–rail interface.

In railway engineering, vertical alignment determines how trains navigate slopes, transitions, and grade changes.

Track geometry design is packed with technical terms, from cant and equilibrium cant to reverse and transition curves. If you're new to...

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