Helix Calculator
Description
A helix is a spiral climb used to move track between decks of a multi-level layout, and it's really just a constant grade wrapped into a circle: each full loop climbs the same amount, and the horizontal distance for one loop is simply its circumference. This calculator works in whichever direction you need — give it the total rise you need to climb along with your helix's radius and either a target grade or a loop count, and it solves for the other.
It also reports the total track length the helix needs, since that's what you'll actually be buying and laying — track length adds up fast in a helix, since every loop is a full circle's worth of flex track or sectional pieces.
Sources
- A helix loop's horizontal run is its circumference (standard circle geometry, C = 2πr), measured at the track centerline — the same radius convention this site's other curve calculators use (see the Track Spacing Calculator's sources). Combined with this site's percent-grade relationship (see the Grade & Elevation Calculator), this gives rise per loop directly — no invented formula.
Disclaimer: this is pure geometry, not a recommended minimum radius or grade. Also budget real vertical clearance between loops — benchwork, roadbed, and your tallest equipment all need to fit in the rise each loop provides — and check your locomotives' pulling power on a continuous curve at your chosen grade.