The whistle fits in the 385W one way. The whistle ground is the whistle mounting to the floor of the tender. The two wires that come off of the whistle run to each truck roller.
Beyond that, everything is the same, wiring, etc. If wiring the chugger and e unit, then it's the same as any other loco with the same stuff, even O gauge.
If you need more info, post again and we'll dig it up. I'll try to find a reference.
