I found this forum while searching for a possible fix for the problem my old HO scale Army Train has. I got this train many years ago when I was a small child, it was given to me by my grandfather who recently passed away. I had it up and running yesterday on a test track made from EZ Track. I was testing some of my old trains that day. I had almost no luck with most of them. But this one was running almost perfectly, far better than the others, but then at some point it just stopped. Now all it does is make a buzzing sound. It still lights up which I suppose is a good sign. I admit I was running it at full speed, mostly because I couldn't get any of my trains to move unless the power supply was set to the max speed setting. The track is old too, but it seems to be in very good condition. When I picked up the train after it broke down to look for issues with it, I heard something moving in it, like a loose or broken plastic gear. But I am not sure if that's what it is. Can anyone help me figure out what's wrong, and how to repair it if at all possible? I've never had to do repairs on any of my HO scale model Trains. I've only ever managed to just barely repair an old battery-operated Thomas Track Master train, but that's an entirely different and much simpler machine to work with. I know my grandpa's old army train is missing a lot of exterior parts, I'm not worried about replacing them yet. I just want to find a way to make this train work again. If it helps, I uploaded a video of it running up until it broke, and a little bit of problem after it broke. The video is on my train themed YouTube channel. I can share the video with you if you want me too. The test track is on the floor in my bedroom, probably not the best place for it, but at this time it's the only place had room to put it. I also had to replace an EZ track piece with a different track piece which fell off a few times, so I tried to support it by placing a plastic road thing under it. I have a few photos of the train, one of them shows the train with the lights on after it broke down, when it started to make the buzzing sound and no longer moves. The other photo is before breaking down, and the last one was of it running at full speed. It didn't crash or fly off the tracks. It did slightly derail a few times however, but only just barely. It never actually left the track. Anyone have any ideas as to what could have caused the issue?