Thanks for the info. Today I won't start yet (it's evening here and I'm up since 05.00) but tomorrow I'll give it a shot without the printed parts. I don't have my slider at hand at the moment but I have just placed the lasercut part of the left side into a slot of the side, an almost perfect fit that wouldn't allow the double lamination with the printed parts, so I think that's clear now
This will be my first locomotive, though I'm a shunting engineer myself.