Examples
Three worked helix builds
Each example below is a complete, opinionated starting point. Click Open in checker and the calculator will load with the example's numbers prefilled. Adjust from there.
HO scale · comfortable
HO mainline with long freight
A typical two-deck home layout helix sized for long modern freight at acceptable grade.
- Scale
- HO
- Radius
- 26 in
- Total climb
- 15 in
- Train height
- 2.5 in
- Headroom
- 0.75 in
- Train type
- Long / heavy freight
A 26 inch radius is comfortable for almost any HO equipment short of 89 foot intermodal flats and articulated brass steam. The 15 inch climb between decks is realistic for a basement layout with a 60 inch lower deck height. Effective grade lands in the acceptable band, footprint is reasonable, and access is manageable.
What to expect: Expect a clean verdict. Use this as a sanity check for what a healthy HO helix looks like before you commit to anything tighter.
Open in checkerN scale · tight
N scale in a closet
A compact helix for a small N scale layout where floor space is the dominant constraint.
- Scale
- N
- Radius
- 12 in
- Total climb
- 10 in
- Train height
- 1.5 in
- Headroom
- 0.5 in
- Train type
- Standard freight
Twelve inch radius is tight for N but workable for short modern freight and four-axle diesels. The climb is modest, which keeps grade reasonable even with the small footprint. This is the kind of design that fits in a closet, a bookshelf, or a hollow coffee table layout.
What to expect: Expect a cautionary verdict driven by radius rather than grade. Test 60 foot passenger cars and any older locomotives before committing.
Open in checkerHO scale · stress test
HO with heavy steam
A larger HO helix sized to handle heavy articulated steam without choking on the climb.
- Scale
- HO
- Radius
- 30 in
- Total climb
- 14 in
- Train height
- 2.75 in
- Headroom
- 1.25 in
- Train type
- Heavy steam / articulated
Articulated and large rigid-wheelbase steam need both radius and clearance headroom. Thirty inches gives the front engine of an articulated some room to swing, and four inches of open clearance covers tall stacks and oversized tenders. The grade is gentle because climb is modest and turns are large.
What to expect: This is what a steam-friendly HO helix looks like. Footprint is the trade — verify aisle and access space before building.
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