When I put one of my Heislers on the track just now the front truck came off! Looks like there are 4 tiny screws that mount the truck to the underside of the chassis that worked their way out of which I found 3. Would Bachmann parts have these tiny screws?

It appears there is a large center screw that the mount with the 4 tiny screws hold on to. I don't see how I can get in there to screw the mount back on to the chassis.

Can someone please help and also where can I find an exploded view of the Heisler?

I've included links to images to hopefully explain what I am having an issue with:

http://loosemonkey.net/images/20231205_140052_1600x1200.jpg
http://loosemonkey.net/images/20231205_140058_1600x1200.jpg
http://loosemonkey.net/images/20231205_140119_1600x1200.jpg
http://loosemonkey.net/images/20231205_140125_1600x1200.jpg
http://loosemonkey.net/images/20231205_140148_1600x1200.jpg

Thanks