The Viennese Bend (R) transition segment is a kinematic high performance transition. The horizontal curvature is assembled by the baseformula and a term depending on the height of the gravity center line relative to the track plane and by the applied cant values at the start and the end of the segment.
The x/y coordinates can be calculated using a 7th order polynominal spiral.
concept {
IfcCurveSegment:ParentCurve -> IfcSeventhOrderPolynomialSpiral
IfcCurveSegment:SegmentStart -> IfcLengthMeasure_0
IfcCurveSegment:SegmentLength -> IfcLengthMeasure_1
IfcSeventhOrderPolynomialSpiral:ConstantTerm -> IfcReal
IfcSeventhOrderPolynomialSpiral:QuadraticTerm -> IfcLengthMeasure_0
IfcSeventhOrderPolynomialSpiral:CubicTerm -> IfcLengthMeasure_1
IfcSeventhOrderPolynomialSpiral:QuarticTerm -> IfcLengthMeasure_2
IfcSeventhOrderPolynomialSpiral:QuinticTerm -> IfcLengthMeasure_3
IfcSeventhOrderPolynomialSpiral:SexticTerm -> IfcLengthMeasure_4
IfcSeventhOrderPolynomialSpiral:SepticTerm -> IfcLengthMeasure_5
}