"Zamac. Zinc, Aluminum, Magnesium."
These die-cast locos are made of a zinc alloy; "Zamak" (not "Zamac") is one of them. Wikipedia: "The name zamak is an acronym of the German names for the metals of which the alloys are composed: Zink (zinc), Aluminium, Magnesiumand Kupfer (copper).[2] The New Jersey Zinc Company developed zamak alloys in 1929. Zinc alloys are popularly referred to as pot metal...." (They are not "German" in origin.)
Contaminants like lead - a very small amount will do it - can lead to "zinc pest" (a warping and crumbling) in cast zinc parts. You'll read about it here regularly.
No aluminum and certainly no magnesium; unsuited for the job and expensive, these two metals are also very light, and a die-cast loco is very heavy, which is a clue.
"What metals are in diecast?"
Any metals can be "die cast"; it is a process. The dies - the "tooling" - receive the molten metal, and when it has cooled enough, the different parts of the die (two or more) are opened and the part is released, then cleaned of extraneous flash and the like.
Die casting is usually done under pressure, as this forces the metal into all the small places (for details in a model's case) in the die. Spinning is also used in more craftsman, "hand made" processes.
