Hi @Drbohlav, thanks alot for the reply and i have gone though the class but sorry didnt find the solution. Please let me know if you find any.
Actually its a limitation of dynamo that it cant get corridor baseline if its created using featureline. That being know what i did is tried creating a dynamic featureline/ without dynamic link also but could not get the polycurve of corridor featureline even if its link is broken with corridor. At the same time i was able to get the geometry of featureline created from polyline.
Currently i can think of only one solution, explode the featureline and get a 3D polyline out of it. then we can get polycurve of 3D polyline i guess.