Hello, new to this board! I've only run HO and N previously but a fun labor day trip to the Sacramento Railroad museum got me curious in Z scale. Just by chance I found the same model Marklin excellent condition briefcase set for sale that was on display at the museum (with better case and slightly different buildings). I was warned of a broken tree and chimney (easy fix with gorilla glue) and a non-running loco (not an easy fix) so was ready to get my hands dirty on this project. After a couple of late nights with a 9V battery on the loco and IPA wipes on the rails, I am convinced the 3-pole motor just needs some TLC. So I upgraded it to a new 5-pole motor and brushes but it still stutters off the line when on the track. A little more IPA on the rails and wheels, still the same problem. Then finally I had a look at the rails with my loupe and see a faint light greenish coating on most of them. Got a nail file and filed away the top surface of the rails using the buffing side until I got constant voltage all the way around. The loco instantly jumped off the line using a spare transformer for control, and kept running. I didn't get to try the briefcase controls yet so I try connecting a used 9V battery to the onboard potientiometer speed control but see some funky readings with my multimeter. The track shows 8V when the switch is thrown to forward or reverse and unable to control. When I place the loco on it, it doesn't move (odd!). After some research on google, I find out the wiring of the DPDT switch is correct (was about to rewire it) and that the voltage readings are normal when there is no load. So I grab a brand new 9V battery and everything now works as designed. Anyways just sharing the results. Pretty happy with it other than the elevation changes aren't really kind on the loco. Would any of the Micro Trains diesel engines fare any better on this layout?