Thanks for getting in touch. Without seeing the scene it's a little tricky to predict exactly what the problem is but it could be an issue with the base spline. Make sure all the vertices are of set to the the type Bezier, or Smooth otherwise you may find that the style is trying to add corners in the middle of a stretch of continuous path. You could also try adding a Normalise Spline modifier to the base spline.
To smooth the spline, increase RailClone's Style > Curve Steps value. You may find that helps.
If you can attach a stripped version of the scene I'd be happy to take a closer look at it for you.