If you are interested. I have the parts to make your engine three rail. I would convert it for the parts exchange I take off of yours.
Another option in a tight space is to stick with four axle units like the EMD GPs or GE Dash 8 or Dash9 B's. (B= 4 axles, C = 6axles.)
I'd buy your engine but I just got a dozen! (or more)