Compound transition curves with different direction

Sorry I don't clearly understand the list of elements you want to create.

Usual case is the S-Curve with no straight so LHRadius-transition-transition-RHRadius. In this case radius is infinite between transitions.

But it doesn't look to be this case.

Hi jpln,

After the  radius (depicted with green color), I need to place 2 consecutive spirals (red in the picture). The problem here is twofold: first, I do not have a curve after to create an S-curve. Second for two consecutive spirals, the end radius of the first spiral should be equal to the start radius of the second one. The radius of the curve in the beginning is 22000. After this curve, I have to place a spiral which goes from 22000 to 50000 radius and after the first spiral, I have to place another one, which goes from 50000 to say -1000. Hope this clarifies my question.

//Filipp Zarov  

So the last one should go from 50000 to infinite to -1000?

Exactly

It means that there is an instantaneous radius of R50000 and inflexion point (infinite radius) to run from +50000 to -8000

Could be done using Add Spiral or Geometry Connector. Probably more tricky with geometry connector because there are multiple solutions. So need to play with parameters and fixity. You may have to click multiple times on Compute to continue iterations if first set doesn't work. If no solution after 3/4 clicks it means that it can't converge.