4.2.4 Laying Curve Track

Prototype Information. See 0.4.5 Curves

The WWSL

The WWSL uses both functional and cosmetic curves. Curves on the WWSL are measured in terms of Radius, in inches. See 0.4.5.1 Degrees of Curvature Table for additional information.

Simple curve The WWSL has established a 21 inch simple curve radius.  This simple curve is located in the helix and an arc of 60 degrees is only visible to the train crew. See 4.2.4.1 Laying out a Simple Curve for additional information.

Compound curve  The WWSL has established has established a 26 inch compound curve radius as the MOW standard. The OPLC has a 28 inch minimum radius for compound curves. See 4.2.4.2 Laying out a Compound Curve for additional information.

Simple Reverse Curve (Turnout) The WWSL has established a 26 inch reverse curve radius (the divergent track radius for Shinohara No. 5 turnouts). The OPLC has established a 28 inch reverse curve radius (the divergent track radius for Shinohara No. 6 turnouts). See 4.2.4.3 Laying out a Simple Reverse Curve for additional information.

Cosmetic Reverse Curve. The WWSL has established a 26 inch compound curve radius with a 28 inch easement connecting to a 12 inch tangent. These cosmetic reverse curves are located in Polson Canyon and consist of multiple curves and easements of approximately 120 degrees in arcs.  See 4.2.4.4 Laying out a Simple Cosmetic Reverse Curve for additional information.

Easements. The WWSL has chosen a simplified easement engineering model. See 4.2.4.5 Easements for Curves for additional information.

Super-elevation. The maximum speed limit on the WWSL is 21 MPH. At that speed prototype super-elevation is not required. The WWSL has one location that could demonstrate super-elevation: the Chehelis River curve, and I will super-elevate that curve for Master Modeler certification. See 4.2.4.6 Superelevation for Curves for additional information.

References

Reference material includes railroad engineering documents, plans, five Railway Engineering & Maintenance volumes from 1929 to 1955, and more.

Walter Mason Camp, Notes on Track, google books Chapter V.

The John Galt Line Railroad Company Spiral Easement Curve Calculator