Bahn okay, car scrap core

I used to like to play with my own Dardabahn. The quality is nowadays unfortunately to be desired.
The train now consists of high-gloss parts with slippery surface. Parts of my old web that are still present, have a roughened surface, after which the grip of the vehicles better comes to validity. This is only the lesser evil, and does not bother really.
The quality of Aufzihmotors contrast, is a disaster. When 3 or 4 raise it once made "clack" and the engine was gone. The supplied vehicle and another spare car the same problem.
Pity!