Recently bought collector edition of Bachmann HO 'John Deere'
train. Diesel tender is too heavy for loco to pull. Unscrewed it and found heavy metal chassis inside with hollowed out section. Why so heavy and what's it for? No wiring inside the tender, just heavy metal chassis.

I recently purchased a Bachmann 'John Deere' collectible HO set. Beautiful work, but the diesel tender weighs a ton and the loco cannot pull it. I unscrewed the body from the frame and found the chassis is solid metal with a plastic mount which looks like it should hold something. What's it for and why so heavy?  Sven44