Just wanted to pass along what happened to me and what I am doing to prevent it happening again. I have 20 loks, 19 steam and 1 diesel. Last month 2 of my newer steamers lost screws luckily I was able to obtain new ones (why does Marklin change part numbers?). I decided to check all my loks and so far after going about 1/3 of them they had screws that were not loose but certainly not tight enough and maybe even from the factory. The wheels needed cleaning on some but I going to clean them all (three wheel I had to scrap off with a toothpick). From now on I am going to do this once a year and when I receive a new lok I will check all the screws before operation. Happy railroading and have a good year - Fred.