Installing a decoder into an Overland locomotive

[2059]

A few months ago I took down my layout in favor of finishing the basement. We made it into a reck room. Now if I want to build another layout it will have to be along the walls so it will be really spread out. My old layout was run by DC but now I'm thinking of converting to DCC. One problem comes to mind. Most of my good locos now will be easy to install a decoder in but my best loco, one of those Overland brass AC6000CWs, has me troubled. It isn't wired like the Katos and the Atlas'. Those models are really easy to just pop a decoder in but the Overland loco seems complicated. Does anybody know the right way to install a decoder on an Overland model? My thought is that I'll have to disconnect all the wires carefully and run them through the decoder. Any help will be appreciated.