Trailing Edge Technology's
Superelevation and Transition Spiral Web Pages
This page and the links below provide an introduction to "Superelevation" (banking) and "Transition Spirals" for railroaders working in all gauges. The examples in the text and default values in the calculator are based on 7½" gauge track, but the calculator and the information apply to any gauge track.
Superelevation is the practice of raising the outer rail in a curve so that the sum of the weight and centrifugal forces is perpendicular to the track. At the equilibrium (or design) speed there are no side forces on the wheels or rails. Transition Spirals are paths that introduce superelevation in a certain, desirable way. For more information, refer to the Primer, below.
These pages are provided in English (Imperial) units only. If sufficient interest is expressed in a metric version, one might be forthcoming. Comments on these pages can be sent to the author at TrackSpiral---TrailingEdgeTechnology---com (replace the triple-dashes with an 'at' sign - @ and a period - .). [This seemingly silly technique vastly reduces the amount of automated e-mails generated by a simple web page being present on the internet.] Be sure to include the name and version of both the browser and operating system used.
Russell Dunn graciously and patiently tested and (by his comments) improved these pages as the sole "Alpha" tester. A group of nine "Beta" testers followed with different and valuable perspectives on both the subject matter and its presentation. Particularly important was the diversity of browsers and operating systems represented.
These pages are provided without any guarantee of correctness. Use them and the calculated results at your own risk.
Change Log.