Re: to Curious =answer

Glad you are curious to ask, as there may be other with the same question.
When you widen the gage from 36" to 36.5" as you go into a 20-degree curve, have 31 feet of track between 36" and 36.25" gage, and then another 31' of track before you get to the place of 36.5" gage in the full body of the 20-degree curve. The rules say to not change gage more than 1/4" in less than 31' of distance of track. If you do not have a spiral covering the start of the curve, you should have some wider gage in the tangent leading to the curve.
If you super elevate the curve it must also be gradual and that is why a spiral curve is much better for operation.
A spiral curve is a curve that has a degree of curvature that increases from tangent (zero) up to the body curve, in this above case: 20 degree. It just gets sharper as you get near the full curve. The length of spiral is usually designed to match the change in super elevation and is half in the body of the curve and half in the previous tangent.
If you had 1" superelevation in the 20 degree, than you should have 1/2" in the part of the spiral where you had a 10-degree curve. It is inversely proportional so the 10-degree is not at the middle of the spiral.