The C&NW SD40-2's had 81" hoods with gong bells, which the Athearn RTR units captured faithfully. They're much easier to model now with the Plano nose bell kit (I did an SD45 that way). I have an RTR C&NW SD40 buried somewhere, but that may turn into a free-for-all because I'd like to upgrade the Rugged Power Products to fit in with my fleet overall--and I'd like that funky gong bell that some SD40s got.
When I built my ex-CGW SD40, I did a Cannonized replacement-in-kind for the old Kato nose and cab, but while I think it's an 81" nose I can't remember. Since the model is currently 6800 miles and 2 continents away from here, I can't pull it out and check, but from everything I divined off photos, the stock Kato nose was correct. I switched to the Cannon cab/nose/sub base because it was easiest to graft a new nose to get the CGW Mars light assembly.
I compromised a little on the light assembly and may fix that someday, but I was hustling to finish the project.
I should add that this started out as a simple renumbering project and fell off a cliff right about the time I compared the factory-painted Kato unit to a proto photo. Not much in common besides the frame and long hood, and when the cloud of AIM weathering powder finally settled, it had received every Cannon upgrade I could concoct, a new fuel tank, traction motor cables, and a host of other add-ons.
Here's the build thread:
www.protomodeler.com/index.php?/topic/1180-cnw-ex-cgw-sd40-927/?hl=sd40#entry11498 Very nice build . I read the post you made building it.
I have never gone quite that far as far as detailing a loco . I have always used mostly BB athearns like the GP38-2 and SD40-2 and replaced the short hoods with cannon hoods or on RPP shells I have used the cannon long hood ends on a RPP GP35 shell and made it a high hood but just used the cannon hood ends and used the short hood roof I removed from the RPP shell and just built up the sides with sheet styrene after of course filing the hood sides for the 81" . I tried using a cannon cab before yet I prefer removing the athearn cabs number board and I always use masking tape to protect the cabs door detail or any rivets , been doing that for decades . I then use testors solvent cement to bond the hood and athearn cab to the shell . I just felt the cannon cab was to flimsy . I also trim the back of the athearn cab so I don't need to fill that gap behind the rear of the cab and the roof of the long hood.
I never cannonized a unit just left the fans and roof and grill details as is. I have removed cast on grabs and lift rings that is a must yet some like the later SD40-2 and GP38-s don't have cast on grabs and rings.
I got more into kit bashing loco's that were not made at the time .
I imagine the latest athearns and Kato's are more correct where the frames do not need to be modified. Mine are BB athearns and the most I've done where needed was remove the shell to frame pins mounts and pads because I can't stand then.
I don't have DCC or sound so I build the unit and paint it and just mask off for the different colors . Well BB athearns walkways are part of the hood so there is no way around it. I'll add MU hoses and stands and lift bars but never added truck air lines or frame details . Perhaps one day I will yet I just don't look that close. I did that once on a Rail power CF7 shell and a Bachmann GP30 . I don't use the RPP fans and so far because of the expense probably won't replace fans with the new DA see through ones. I was not even aware they had the new ones until this year .
My gripe has always been why any manufacturer would cast on grabs like Atlas used to. I removed plenty of them then suddenly Atlas made in China left them off and had frame mount couplers .
I just have older stuff to work with and get as close as I can to the real thing and I'm happy with that. I had later PK2's and some Atlas but then with all their detail my older builds didn't quite match up .
I used to build a few units and detail them say three at a time then paint them and finish them then I got carried away with kit bashing Baldwin/EMD re builds and Alco/EMD re builds like C&NW had and Katy had.
Now I want to finish what I started and the few RPP shells I have just need hood ends and 81" short hoods and the detail parts as does one athearn SD40-2 a 81" short hood and I already cut the fuel tank for Milw road . I didn't cut it to the exact 16 feet because I didn't want a weak frame , I left 6" more and sort of tapered the front of the cut fuel tank so it doesn't show just to have a bit more frame support . It's like the stock tank has simulated brackets about 3/32" from the frame rails so I trimmed the tank to 16.5 scale feet and flush with the frame rail sides but tapered the 2.5 feet x 3/32" left and beveled the sides and the frame feels solid and looks close enough . I had an extra frame so I used that as a test the I will do the other one or I may just do one Milw and the other C&NW .
The rail Power frame for the RPP SD40 shell does have the proper frame rails you added to the Kato SD40 frame and that tank is easy to shorten and still have ample strength.
I do like all the detail work you put in your SD40 , nice job man .