Scratchbuilt BNSF SD40-2’s – Latest Developments.

The progress thus far on one of the two BNSF SD40-2's that I'm scratchbuilding.

I’ve been slowly but steadily plugging away on the two scratch-built locomotives I posted about back in May.  I’m at the point now where most of the major challenges, such as gear tower clearance, coupler mounting, etc. have been solved and I can begin to focus more on the aesthetic side of the model.  The last major hurdle will involve the nano LED’s for the ditch and step lights that I need to wire up and attach to the model so that the leads will be sandwiched under the treadplate.  That process will likely begin after the holidays.  Select images and info are past the cut.  A full gallery is available on my Pbase site.

An SD40-2 frames with the fuel tank and draft gear attached and trucks and motor mounted.

Along with modifying the frame, I also had to modify the trucks.  The front of each gearbox had to be angled slightly to clear the RFMP draft gear and the molded on traction motor detail had to be cut off to make room for the Details West replacement.  I will also need to carve some material off the gear tower on both rear trucks so that they will clear the end of the long hood.  This has been the most frustrating part of this project.  Athearn really needs to update their SD trucks, they’re far too bulky.

The couplers mount in much the same way that they do on a standard RFMP frame, though the draft gear is not attached to the back of the pilot to facilitate removal of the frame.

After attaching the pilots, stepwells and sidesills, I built the coupler pockets and attached them to the pilot faces.  They required a bit of filing to get the Sergent coupler shank to fit, but not enough to change anything visually.  Next I will add the draft gear bottom plate, then secure the entire assembly with  countersunk 1-72 3/8″ flathead screws that I will drill and tap the athearn frame to accept.

That’s it for now.  I’m moving in January, so most of my modeling projects are on hiatus until I’m settled in my new place.

– Chris

7 thoughts on “Scratchbuilt BNSF SD40-2’s – Latest Developments.

  1. Yes. All the brass that you see is Railflyer. Also, the draft gear, coupler pocket and fuel tank.

  2. I’d be interested in having a detailed post on adding the step lights. I think that would be neat to add to my locos but would love some specifics to get me started.

    • Hi David,

      I plan on providing some more info on the step lights, I just haven’t had a lot of time to work on this project. Starting the layout and trying to finish up my SNCT F7A have taken over my life at the moment.

      – Chris

  3. Chris,
    I am finally going to have Tony Sisson mill a couple of SD45-2 frames for me. I am pretty much going to steal your ideas for building back (as I have plenty of Railflyer parts) Do you know how much you had milled of the bottom area of the fuel tank area?

    Thank you,
    Todd Carlson

    • Hi Todd,

      I’m not entirely sure of the amount of material removed from the bottom of the tank, but the final iteration is .326″ from the bottom of the frame to the bottom of the fuel tank. That won’t create a flush fit with the RFMP tank, to do that I glued a piece of .040″ styrene to the bottom of the frame and then sanded it down until the tank sat where I wanted it to (you might be able to use .030″ styrene and not have to sand, you’ll want to test.) I also put strips of .015″ or .020″ styrene at the end of the tank blob (on the bottom of the frame) for the RFMP plastic to sit on. These provide clearance for the photo-etch end plates, which sits just proud of the top of the plastic tank.

      Here’s a photo of one of the original frames with the areas to be removed marked out:

      Did I send you the drawings I made? They have all applicable dimensions, if you need them, let me know and I’ll get them to you.

      – Chris

  4. Chris,
    I would appreciate it if you would send the drawings that you made. I don’t know if you have my email address. I sent you a friend request on FB. I have 5 frames that I am going to have Tony mill for me. I think that we will see a Genesis SD40-2 announced with in the next 2 years. So I have going to use these for other projects that use the SD40-2 frame.

    Thank you,

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