4.2.4.6 Superelevation for Curves

Prototype Information

 

Engineering

 

The WWSL

 

Modeling Information

There are three ways to model superelevation for curves. 

First. Tape      . 

 

Second. Stripwood

 

Third. Canting the subroadbed. 

 

I am going to use the first technique: tape.

Project Process

1.  Layout the curve

2. Layout the superelevation

3. Lay the track.

During the building of the curve templates, we had marked, on the templates, the transitions from the tangent (straight) to the spiral, the spiral to the arc of the curve, and then at about every 11 degrees through the curve(45 /2 ~= 22, 22 / 2 = 11). These markings were transferred to the roadbed when the templates were used.
 

We used thin (1/4" wide) strips of masking tape under the location of the outside rail on the roadbed to elevate the rail. The first layer(s) starts on the tangent about a foot before the beginning of the transition spiral to hike the train up before it enters the curve. The strips of tape go all the way to the corresponding location on theother end of the curve. Another layer (or layers) goes from the beginning of the transition spiral through the curve. The last layer(s) go from the beginning of the arc of the curve to the end of the arc of the curve. We had fairly thin masking tape, so we used 2 layers, 2 more layers, and then 3 more layers (total number of strips = 7) for ours. Thicker masking tape might require something less. The effect is subtle but noticeable. 

Once the track is down, ballast as you normally would. You can cut the strips on a sheet of glass with a razor knife and metal-edged ruler.

 

Reference

Mark Couvillion, Laying Out Easements with Transition Spiral Templates in HO,  The Derail — October 2017