Now you have me puzzled.
This issue has nothing to do with "Effect Layers" as the assets have to be placed, not painted, onto the track. Where is the "reported bug" in the "Edit Effect Layers" section of the document you referenced in the link (and I wrote that document so I know).
What scrapbook? Is there a scrapbook asset that contains these items? If there is then I can see lots of problems with placing them onto existing track. Like effect layers, scrapbooks are normally painted into a route, not placed. However, they can be placed using the Paste command (Ctrl+V keys) but that would be extremely tricky to do and would not allow for curves or other features of the track. The only "scrapbook issue" is that scrapbooks cannot contain rolling stock objects.
Your statement "placing them individually is not the problem" means that there is no problem with these assets - from what I can see they are working exactly the way they are intended to work. You simply have to place them individually and then, somehow, add the wire as a spline. That is a lot of work.
