GP38-2 and GP40-2 vs GP-38 and GP-40

[blane]

I'm hoping to find some help with prototype information between the GP38-2/GP40-2 models and the original GP-38/GP-40 models. What were the visual differences between the 70s dash 2 models and the 60s original models? Also, how would these changes be done to an existing Athearn Blue Box GP38-2 and GP40-2?

Blane

[deez]

Depends on if you want real accuracy or just the general look. There's literally so many differences that you're better off just acquiring an Atlas standard GP38 or 40 shell. Cab, battery boxes, blower hump, dynamic brake blister and toughest would be the radiator door changes. These are among the biggest differences.

[blane]

I guess I want enough changes to make it look enough like one of the 60s model. However, the idea of an Atlas shell on an Athearn frame would work well as well. I've been debating about using an Athearn SD-9 frame and putting an Atlas SD-35 shell on top in order to have dummy units. Plus Atlas stocks parts well so getting a shell shouldn't be difficult.

Blane

[emd16645]

Keep tabs on eBay and you can find complete atlas GP38/40s for very good prices. Buying a shell piecemeal won't be much cheaper, and the Kato clone drive in the atlas out performs athearn by so much it's nearly worth the price of the atlas in the first place.

[chessie8553]

The tricky thing with EMD's is that despite the fact that the GP38/40 and the early versions of their Dash 2 successors look a lot a like, they share virtually no sheet metal. You could use an old Blue Box GP38-2 or GP40-2 and back-date some of the details, but it wont be 100% accurate. In fact, I have done this very thing myself and the overall result is pretty good. You could go all the way with Cannon parts and what not, but by that point you may as well just go on and get the Atlas model.

[blane]

I'd still like to give it a try since I have a use for one of my GP40-2s as a GP-40

[deez]

The money it would cost to buy just the basics for the change would be more than an Atlas shell would cost. It really makes no sense to do so. Save the -2 shell for another project. Or do something simple to the 40-2 shell like changing the radiator grills and radiator fans to make a phase 1 GP39-2. It'll put that Athearn shell to better use and look good.

[prrhorseshoecurve]

Some basic differences.

Gp40 and a gp40-2. ; Gp40 had a gp 38 type rear cooling grill, 81" nose on a gp40. And no extended range dynamic brake on the Gp40-2. Gp40-2 had bigger sd40-2 rear cooling grills, an 88" nose, extended range dynamic brakes(longer sheet metal on fireman's side) gp40-2 sight glass on long hood engineers side

Gp38 and gp38-2; GP38 had two rear cooling fans more forward on long hood than a gp38-2. Gp38-2 had sight glass on long hood engineers side, a box paper air filter structure ahead of the dynamic brake and cooling fans pushed back more rearward on the long hood roof.

[sgoti]

Aug 8, 2016 17:23:07 GMT -5 prrhorseshoecurve said:

Some basic differences.

Gp40 and a gp40-2. ; Gp40 had a gp 38 type rear cooling grill, 81" nose on a gp40. And no extended range dynamic brake on the Gp40-2. Gp40-2 had bigger sd40-2 rear cooling grills, an 88" nose, extended range dynamic brakes(longer sheet metal on fireman's side) gp40-2 sight glass on long hood engineers side

Gp38 and gp38-2; GP38 had two rear cooling fans more forward on long hood than a gp38-2. Gp38-2 had sight glass on long hood engineers side, a box paper air filter structure ahead of the dynamic brake and cooling fans pushed back more rearward on the long hood roof.

Umm... Almost.

Both the GP40 and GP40-2 could have chicken wire radiator grills, depending on build date. I think the change to corrugated grills came in 1977.
Early GP40-2s had 81" noses, change to 88" nose came in 1977 (I think).
Late-model GP40s had extended range dynamic brakes, on BOTH sides of the locomotive. They also has the -2 style traction motor blower bulge with two horizontal stiffening ribs.
There was no change in the length of radiator grills from the GP/SD40 and GP/SD40-2, only a change from chicken wire to corrugated grills.

The fan SPACING changed on the GP38-2, not the location. The rearmost fan was always in the same location. Early GP38-2s (L&N 4050, for example) had the wider spacing of the earlier GP38 models.
GP38s usually had the radiators split into two sections (corresponding with the wider spacing), and had chicken wire type grills. GP38-2s could have radiators grills in two chicken wire sections, one single chicken wire grill (with closer fan spacing), or one single corrugated grill (with close fan spacing).

[deez]

One thing to note about extended dynamic brakes. It is not the forward faring extension of the sheet metal that makes an EMD have extended range dynamics. Extended range is an actual option added to locomotives to further enhance the dynamics in lower speed situation. It is identified by a latched door. On one or sometimes both sides of the dynamics. The forward extension of sheet metal on '71 and newer EMD's is more for access to the contactors. The contractor door should not be confused for the extended range option either as it is not a latched door. It is hinged and located at the end of the faring on -2 dynamics. It lifts up. Where as the latched extended range door drops down.

[sgoti]

...And I knew some of that, just failed miserably to make the distinction.

Thanks for the clarification.