Is there any tutorial explaning how to design turnout feature definition

Hi, I want to create my feature definition for differents turnout that we use.  Our turnout cell are very simples, basicaly 2 lines with an angle between them.  But I just can't figure out how to create a turnout definition.  The help file is almost empty.  Does anybody have an idea what are the setting, how many element should be used in the feature definition?  Do I need to create a curved element?  I'm sure I am not the only one strugling with this?

Thanks for your time