According to IMW's web site, the kit is intended to 'accept' RDC drive parts. The RDC drive parts hardly 'drop in', but IMW gets the builder most of the way there. The motor mounting holes, for example, are spot-on, but need to be carefully drilled out to accept the soft RDC motor mounts.
The drive truck mounting hole in the IMW needs very careful reshaping--it should be identical to the mounting hole in the RDC floor. Its 'length' is correct, but its 'width' is not. This may be a leftover from an earlier, Life-Like iteration of the RDC drive, but it was not correct for the drive components from my Walthers RDC drive. The position of the truck mounting hole and the motor mounting holes allow use of the motor and the universal shaft without any modifications to those components.
One of the included bolster adapters or sheet brass or styrene should be used for the non-drive truck. I used .080" styrene sheet plus a bit of styrene rod as a boss for my non-drive truck bolster. Were I to do this over again (or build another one of these kits in the future), I would use a long piece of heavy brass stock as bolster, stiffener, and weight.
Speaking of stiffening and weight, I epoxied heavy brass strips between the motor and and non-drive bolster to give the floor some rigidity and heft.
I used the brown plastic motor saddle (minus most of the seats) and a block of 3/4" x 1/4" basswood as supports for the lighting/DCC board.
Once wired back up and circuit-tested, the new drive worked quite well. I installed a Digitrax DH165IP decoder. Check out the video below to see the drive and the partly assembled coach in action.
The car body will now be the focus. In addition to adding pantographs and various other appurtenance details (horns, bells, wire grab irons, etc), I will rebuild the pilots and steps as part of the coach body. The cleanly-molded and prototypically thin RDC steps will be recycled here. Also, the pilots will be scratchbuilt from styrene to replicate the 'flat face' look of the prototype--the kit as engineered has a large seam between the car end and the pilot, which doesn't look right to me. Then on to window glazing, painting, and finishing.