Send them to me (free of course)
You'll still have a DC motor in them, gut the engine except for the motor, and run DC to the outer rails and center rail. You'll no longer have all the bells and whistles (literally) but your engine will run.
Convert them to BPRC (Battery-Powered, Remote-Control) like I converted all my steamers (using a system from RCS in Australia) if you want wireless control (I have ZERO wires on my layout now). I've converted 7 steam engines since May this year, MTH, Williams brass, and a Weaver/scratchbuilt 4-6-0. My Williams brass N&W 4-8-4 Class J (all 14 pounds of it) runs fine on a 11.1v LiPo battery. Right now I have no sound, but an engine with dead electronics has no sound either.
Of course the RC electronics will die too, but I expect there will always be something else to take its place, if not, revert back to my first suggestion DC motors will be around for a while.