It’s easy to find flat metal pieces of weight for coaches and locomotives, but where can I find a cube like weight to glue into a locomotive?
Large fishing sinkers come in various sizes and can be further shaped with a hammer and vise.
BB’s and lead shot can be poured into shells and openings with white glue poured over them to seal them in.
Stack a lot of flat plates together… Or, get into the casting field, and cast your own with the low-temp alloys like Cerro-Bend.
Automotive wheel weights can be attacked with vise jaws, hammer and pliers and beaten into almost any shape. Ditto for large fishing weights.
If you saw or file them, use a respirator mask and be sure to clean up and segregate the dust and shavings. Adding lead to landfills and/or the general environment is frowned on.
Chuck (modeling Central Japan in September, 1964)
I melt old wheel-balancing weights with a propane torch, then cast weights to suit the particular model, using moulds made from thin aluminum sheet.
Wayne