So the OP is RkyGriz, and apparently he got he answer.
So RR Dave, you have a new set of questions. The S4 uses different motor blocks from the GP7/9.
The 44 tonners are in very short supply, again different motor blocks since the coupler mounts on the truck.
I have two 44 tonners to match the 2 paint schemes that Santa Fe had. I also have a used one a club member wanted to sell, but all the axles need replacing. The body is fine, the motors are fine the axles need replacing due to someone taking it apart and reassembling wrong. The cost to repair is almost what the used value is in my opinion, but again these are scarce. Email me if interested, it is a Burlington
You are really pushing the limit with R1, you should stick to really small stuff. I am not sure the 44 tonner would negotiate those curves, nor would knuckle couplers work well. It's not just the wheelbase of the motor block, but the length of the loco, and really how far the trucks can swivel in the chassis. I only had R1 curves for a few weeks when I found virtually nothing I wanted to run would go around them.
I'm afraid you are stuck with short locos and short cars, and perhaps even hook and loop couplers in many cases.