Yes, it has to be hard wired, but there is room in the locomotive boiler for a decoder. I have put decoders into several IHC steam engines by soldering them into place.
It was really easy to do, if you have any soldering experience, because the motor brushes are already isolated. All that was involved was to unsolder the wires that are attached to the motor brushes, splice those wires to the decoder's red and black leads, cover the solder joint with shrink wrap tubing, and then solder the decoder's orange and gray wires to the motor terminals from which the original wires were removed.
I left the headlights as they were because they were soldered separately to the front set of drivers. The headlights are always on, which is no big deal.
Some IHC steam engines had enough room inside the boiler for a TCS T-1 decoder and some required something smaller, such as a TCS M-1.
Been Nothing Since Frisco (BNSF) How could I possibly put a DCC decoder in a IHC 4-6-2? How would I? I dont see a plug anyware? Harde wiring?
How could I possibly put a DCC decoder in a IHC 4-6-2? How would I? I dont see a plug anyware? Harde wiring?
Hard wire, if there's no plug. See if this helps.
Gary