I found this place while looking for small DC motors and gear boxes. They have WAY too many neat things. I have no affiliation with them, but I received my first order today. They have 'broken' walking toys. These have a neat gearbox that should make a nice little Gn15 steam critter. The things come 'unbroken' but break instantly when the dog gets them. They are actually quite a nice design, a walking toy that WALKS. But the pinion gear on the motor is too thin and cracks with the least pressure from the very long legs on the animals. I think it will work fine for a small loco. I put a drop of super glue on the cracked pinion and it works fine now.
I was hoping for a Giraffe, but got 3 Boxers. No biggie, the dog doesn't care and the loco won't either. I thought the Giraffe head would be cool sticking out of a box car.
I also ordered some gears and this gearbox: