Yes, is this the green one? I have a M37521from 2002 or 03. Poor quality of the frames, and gears. Zinc pest in the frames can also seize the gears. Subsequent versions are improved.The new Marklin ownership provided no warranty coverage for the poor quality control of the former Kings bridge capital ownership.
I don't know if the gears are interchangeable. An Italian fabricator made replacements. Still might. Frames too, but they are expensive and I think it's more economical to get a new model, with sound.
Mine has been retired as a shelf queen for years because one nose frame has detached from the center and the cardan shaft doesn't stay in the worm gear socket. My gears looked ok last I inspected it.
A post from December 21,2017 covered these models with the defects. Crumbling Crocodile
I just bet that a good gear blueprint could be programmed to a 3D printer and using the best type of polymer new ones can be made. Other brands have used Delrin gears. Whichever Roco uses, they last a lifetime.Red, black and white colors.