Telltale Diff btwn GP7 and GP9

[rainierj]

Can anyone please tell me what are the telltale diff's between these loco's?
What to look for. I want to buy 2 ATSF for a consist with sound, where would be the best place to buy? [:)]

[jrbernier]

GP7 - has 2 full sets of double louvers ar the rear of the long hood, and 3 single ones on the battery box under the cab.

GP9 - a single set at the rear of the long hood, and a single set on the battery box under the cab.

Jim Bernier

[trainboyH16-44]

How great our knowledge is....knowing the difference between 2 locos by 1 set of louvers.....

[Southwest Chief]

Where are Santa Fe GP7's available with sound?

I'm doing mine the hard way...installing a soundtraxx decoder and speaker in my old GP7. Well guess not too hard as it is sort of plug n play. But still going to be tough getting a speaker in there.

[ndbprr]

You may have to do some research to get it right. the PRR bought over 300 GP-9's and they came with both small fans and large fans over the radiators on the roof. So you may have to find a proto picture of the number you want to model

[scubaterry]

Southwest chief - I just put sound in a LL GP-9 and a LL GP-7. I used my dremel to take out a small portion of the front chassis and put a 1 1/2 x 3/4 in oval speaker facing down towards the front truck. It sounds much better in my opinion than my GP-9 w/QSI sound. I have pics if you are interested.
Terry and WILMA for now

[rrinker]

Just don't fall into the Athearn and Lionel trap of calling a unit with dynamic brakes a GP-9 and one without a GP-7!

--Randy

[cefinkjr]

The only fool proof difference that I know of is a little rectangular plate on the lower side of the cab (or near the front of the frame) with "GP7" or "GP9" on it --- if said plate is still there after all these years. [:D] [}:)]

Chuck

[Anonymous]

So can you tell these apart?
http://www.trains.com/community/forum/topic.asp?TOPIC_ID=47756

[andrechapelon]

QUOTE: Originally posted by Lotus098

So can you tell these apart?
http://www.trains.com/community/forum/topic.asp?TOPIC_ID=47756

Yup.

Andre

[dknelson]

It can be a challenge because often after rebuilding there was so much new sheet metal that the louvers had been changed or covered over. And often the GP7 or 9 plate was removed by that time.
In the very early 1950s the then editors of Model Railroader used to claim that the difference was that GP9 had a dynamic brake indicator and the GP7 did not, which was simply not the case. But this was back when most model railroaders were grumpy steam fans who insisted all diesels looked alike and since that is what they thought, they didn't look for the kinds of differences that actually did exist.
Dave Nelson

[fuzzybroken]

Number of horsepower in the engine [:D] Or better yet, whatever the railroad calls it!!!

Seriously though, the two engines were so similar that either one could easily look like or "become" the other. Even some GP18s suffer the same confusion, as I have seen pics of a GP18 with GP18 radiator screens, but with four 36" fans!!! As pieces get swapped between units, new sheet metal is used, even the engines themselves can get changed, or derated or occasionally uprated.

So if you want absolute accuracy, a picture of the specific unit you want to model is imperative, but if you can live with less than accuracy, you can find an acceptable compromise somewhere in between absolute accuracy and a warbonnet Geep with large Santa Fe lettering!

In general, GP7s and early GP9s had four 36" fans over the radiators, while later GP9s and GP18s had two 48" fans over the radiators, and GP18s had different radiator screens.