Difference between gp7 and gp9?

[Bayfield Transfer Railway]

The difference between a GP-7 and a GP-9?

2.

 

*runs like hell*

 

[Redore]

The only dumb questionsc are ones you don't ask.

 

As I understand it, as delivered the access to the class lights and roof are individual rungs attached directly to the hood ends on most GP and SD-7's and fabricated ladders on stand offs from the ends on GP and SD 9's.  This could be changed in the 50 to 60 years since.

[7j43k]

arbe1948

Also, ACY, if I recall, wasn't the original Athearn SW 1500 actually SW 7 or something like that?

 

 

It was pretty much an early SW7 body with a late SW7 cab.

 

Ed

[arbe1948]

Also, ACY, if I recall, wasn't the original Athearn SW 1500 actually SW 7 or something like that?

[ACY Tom]

I typed complete answers twice. Just as I was about to hit "submit", a response was posted by somebody else and my post disappeared.

Briefly, look at pictures. Take note of the shape of the side sill (plain on GP7's; shaped differently on late GP9's), the presence or absence of slots in it (present on early GP9's), and the locations and numbers of louvres in the hood sides and grille sides (more of them on GP9's). The louvres under the cab, mentioned by Rick, don't seem to be a consistent feature. I see them on photos of B&O GP7's, but not on NKP GP7's.

GP7's used 36" roof fans. By the end of GP9 production, all roof fans were 48" diameter. 

Dynamic brakes, "torpedo tube" air tanks, etc. are irrelevant, as they were options available on both models.

The GP7 produced 1500 h.p., and the successor GP9 produced 1750 h.p.

Tom

P.S.: No, Charles, you're not dumb. The wide-body BB Athearn "GP9" was on the market for about 20 years before some eagle-eye realized it was a GP7. This was about the time that Tony Koester and others opened the eyes of many of us and began to promote the idea of better accuracy.

P.P.S.: I managed to get all the material posted by posting a short item, then adding to it with edits. Frustrating.

[7j43k]

Trainman440

Hi, maybe Im just dumb, but whats the physical difference between GP7 and GP9?\

Thanks

 

 

We wuz all dumb, once.  Then we learned stuff.  Frequently by asking.

 

I am assuming, when you use the word "physical", that you mean "what you can see by looking at it from the outside".  Because there are also physical differences on the inside.  Which don't mean a whole lot to modelers.

 

And, frequently, as Rick just implied/noted above, there are subgroups of "physical", called phases.  And there can even be subgroups in those subgroups.

 

There are various resources that discuss phases, both on-line and bookish.  One of my favorites (though it doesn't have GP7/9's) is:

 

 

http://www.trainweb.org/jaydeet/rosters.htm

 

Ed

 

 

Ed

[dti406]

According to original "Diesel Spotters Guide" on pg. EMD-25, "The GP-7 has three or four louvers below the cab and two vertical rows of louvers under the radiator shutters at the far end of the long hood. The GP-9 has one or no louver beneath the cab, and lacks the two vertical rows under the radiator shutters. Presence or absence of the dynamic brake blister tells nothing, as both GP-7's and GP-9's came with or without dynamic brakes.".

Also on later Phases of the GP9 the 4 36" Radiator Fans became 2 - 48" Fans, and after many railroad modifications all spotting differences may become moot points.

Rick J

[Trainman440]

Hi, maybe Im just dumb, but whats the physical difference between GP7 and GP9?\

Thanks