Look at your inputs.
You’re telling it you want implied curvature along your rail (which is what you want based on the picture) AND implied curvature along your generation curve.
This means it’s screwing everything up trying to generate curvature in those 2 directions.
Set your gen curve to free and it should let it flow properly. If you are actually trying to achieve implied G2 on your gen curve, then that’s a whole separate discussion and you shouldn’t be trying to use a monorail 1.