Can't say if this will work, and the thickness of the diecast can have a lot to do with whether the part will hold together or not. Try J-B Weld, a 2 part epoxy that dries pretty strong. Use the slow drying formula, it will somewhat blend in with the loco color. I have used it on a carbuerator and am currently working on a kit bashed signal bridge, which I have filed & carefully dremmeled some areas to hide some flaws. (never easy, but doable). Don't buy the fast drying formula.
Steam Forever
John