A puzzeltask

[Kernelpanic]

4) Drive G-L forward (right at bottom switch) and leave G somewhere along rail D.
5) While on rail D, push Co into the bumper slot A.
6) Drive L (nakedly) through C, onto D, and then reverse to drive toward the viewer, switching appropriately.
7) With L on the viewer's rail, drive forward and hook to Co.

That reads as if you wanted to turn the locomotive around... That doesn't work. The locomotive can only drive forwards and backwards.

And this position on D is wrong: *) At this stage, rail D should have the configuration L-Co-G.

The position/combination on track D must be here: G - Co - L 
That's half the solution now.  When one have reached this position, one have overcome the psychological block.