Gandalf, it is a pain, that is for sure. You say you pushed them through the support first. Does that mean you came up from the bottom. I have been trying to put them through the two spacers first, then the metal clip then lastly into the "wooden" trestle. They seem to go into the trestle well in the end, but it is the 3 metal pieces that have me crying. 
Thanks
Todd
I started out doing it the way you are but popped the metal part that clips onto the track on last. It goes on pretty easily. I very quickly gave up on the spacers.
What I am doing now is replacing all my trestles. I'm going to use Woodland Scenics inclines and risers instead. They will look ugly until I get to adding the colored foam but they will give me better support than what I currently have.
