?Running wires beside the smoke unit?

[Boyd]

Yet another question about wiring two Lionel 4-4-2 steamers together. If you have not seen my  other posts,, I'm running a tether wire between the two engines which both have "can" motors. In order to keep it looking neater I'm thinking of running the wires for the trailing engine ahead inside the shell and around the side of the smoke unit. I'm guessing just the very bottom portion of the smoke unit gets really warm?