I agree with making one out of strip styrene since you don't need a metal to metal bar for current transfer from the tender to the engine unless that loose wire at the back of the cab was somehow connected to the original draw bar for electrical pick up. If the original was metal to be part of the circuit then a piece of strip brass should be used. Either way, a little flat black paint and its done.Athearn/Horizon Hobbies should be able to help. If not, I suggest visiting a local hobby shop and purchasing a sheet of 2.5-3mm styrene, and fashion your own.