Re: Banked Curves on the Narrow Gauge

The cord is gage of the rail to gage of the rail on the inside. The measurement in inches at the center of the cord is the amount of superelevation. And if I was measuring it, I would mark a station every 31 feet and take a new reading every 31' from -50' tangent to tangent +50' so the rise is gradual as you go from tangent into the full body of the curve. You want the superelevation to match the change from tangent to curve. For narrow gauge and such low speed, a spiral in the start of the curve surely is not necessary.

If you come up with different measurement within the body of the curve, you do not have a correctly aligned curve and you should string-line and repair it to be a constant curve.