Please see attached picture.
Here are a few things to do.
In the two rail sweep options , choose the " Fill center of inner closed vector".
That way you'll only need one component.
Two, after selecting the two rails and the profile, click on the outer rail where to place the profile.
In this case I've click on each corner and then adjusted the inner "node" of the shape to align with the inner corner..
I hope this helps.