I just recently puchased a GTW unit off ebay for my small layout. The description said it was either a GP7 or 9, the seller couldn't tell. There was a video on Youtube that explained this but I can't find it, plus it was for Conrail, not GTW. Can anyone explain this to me?
Crap happens. When it does, stop, take a deep breath, and call the wreck train.
Here's your You Tube video
http://youtu.be/NVXq-TeI0ss
Hardly makes a difference which RR. For the most part EMD is EMD. This guy seems to do a pretty decent job in explanation with visuals.
The way I determine GP7/9 is by the wings behind the cab. If it has wings, it is a GP9. No wings=GP7. A picture of what you have might also be helpful.
I might be wrong on this, so don't hold me to it! If I am wrong, someone else please let me know!
Acela
The timbers beneath the rails are not the only ties that bind on the railroad. --Robert S. McGonigal
Those wings are actually the dynamic brake apparatus. They could be found on GP7's as well.
-Stan
on the GP7 there are 3 sets of louvers under the cab and the forward walkway. On the GP9 there was either 1 or none..
B&O1952 Those wings are actually the dynamic brake apparatus. They could be found on GP7's as well. -Stan
Still to late to blame childhood innocence?
GP7 and the GP9 were hood unit versions of the F7 and F9. The horse power of the GP7 was 1500 HP and the horse power of the GP9 was 1750 HP. The GP9 also had a larger dynamic brake fan and could offer a higher level of braking capacity than the GP7's. This capacity was facilitated on the GP7's (36-inch axial fans) the GP9's had 48-inch axial fans.
Rio Grande. The Action Road - Focus 1977-1983
The easiest way to tell in most cases is to look at the vent louvers beneath the cab. If there are 3 it's a GP7, if there is 1 it's a GP9. I have seen a few models (rebuilt by their owner) that have the larger dynamic brake fan of the GP9 but the 3 vent louvers of the GP7. These models represented GP7's that were rebuilt into GP9's in a quick and dirty fashion.
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
For a model engine, using the vent louvers to distinguish between the two models is probably OK. It should be noted that the louvers are on the battery box covers and are interchangable. Many times shop forces weren't always too particular when replacing the covers.
Jeff
Hmm... the title of the thread is: "GP7's and GP9's- Whats the difference", not how can you see the difference? I realize we have to imagine how a model railroader would think and that is how you interpreted the question, not literally but what you thought the OP wanted to hear.
Anyhow, going by what is posted an the fact that some parts can be interchanged, I guess the only real difference is the horsepower and not the louvers. As delivered, the louvers below the side cab windows are a spotting feature as are the db fans on the roof.
GP7
GP9
Dynamic Brakes can be order for either a GP7 or a GP9(optional equipment). The original GP7's had a 36" fan over the D/B blister. In mid-1952, EMD changed this to a 48" fan due to D/B grid burnout issues. All GP9's were delivered with the 48" fan if they had D/B's. Many D/B GP7's were 'upgraded' with the 48" fan later in life, so seeing a 48" fan really does not mean you are looking at a GP9. Check the louvers.
I do not think GT or GTW ordered GP7's. The Canadian owned lines dieselized late and for the most part got GP9 or later engines. I know GTW did get some F units for road service, but they were still running passenger trains with steam engine in the late 50's!
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
jrbernier GP7 3 sets of louvers under the cab 2 double sets of louvers at the rear of the long hood GP9 A single set of louvers under and just forward of the cab A single half set of louvers at the rear of the long hood Dynamic Brakes can be order for either a GP7 or a GP9(optional equipment). The original GP7's had a 36" fan over the D/B blister. In mid-1952, EMD changed this to a 48" fan due to D/B grid burnout issues. All GP9's were delivered with the 48" fan if they had D/B's. Many D/B GP7's were 'upgraded' with the 48" fan later in life, so seeing a 48" fan really does not mean you are looking at a GP9. Check the louvers. I do not think GT or GTW ordered GP7's. The Canadian owned lines dieselized late and for the most part got GP9 or later engines. I know GTW did get some F units for road service, but they were still running passenger trains with steam engine in the late 50's! Jim
Actually some early GP9s also had the three sets of louvers under the cab. The most reliable spotting feature is the pair of vertical louvers at the rear of the long hood. You are quite correct in stating the GTW never ordered GP7s, perhaps because their initial phase of road dieselization used F3As. To completely eliminate steam later on they bought GP9s and even some GP18s. The parent corporation, CNR in Canada, did get about 25 GP7s, but something over 300 GP9s. I believe the GTW GP9s came without dynamic brakes while CNR normally specified them.
John.
Thanks to all that replied. The unit is indeed a GP9 with GP7 horns. How this is possible lies with the original design specs of the unit company. Anyway, please check out my new post Lionel HO GP9s-How do you get them running?. The loco featured is my new GP9, GTW 5511 and I can't get it to run on the layout.
B30-7CR Thanks to all that replied. The unit is indeed a GP9 with GP7 horns. How this is possible lies with the original design specs of the unit company. Anyway, please check out my new post Lionel HO GP9s-How do you get them running?. The loco featured is my new GP9, GTW 5511 and I can't get it to run on the layout.
As it happens my LHS is selling out their old VHS tapes at 75% discount, and just last night I watched a "new" video I had bought put out by Trains on "Geeps" early history. One of the EMD engineering guys was interviewed and explained that they found out that one 48" fan could do the work of two 36" fans, so making that change eliminated some moving parts and made the GP-9 a little more reliable. IIRC the GP-9 frame was quite a bit stronger than the GP-7 frame; early GP-7s had some problems with frames bowing and such. I don't know if it would be visible on a model or not.
p.s. as designed in 1949, the GP-7 was meant to be a 'no frills" locomotive, and did not have the option of dynamic brakes. It was later added as an option, but many / most GP-7s didn't have dynamic brakes. By the time the GP-9 came along many railroads decided they liked dynamic brakes on road switchers and ordered them with dynamic brakes. Because of this, many more GP-9s had the dynamic brake "blister" on the long hood. This lead some model railroad manufacturers to assume that GP-9s had dynamic brake blisters and GP-7s didn't, so the called their GPs with dynamic brakes a GP-9 and the ones without dynamic brakes a GP-7. Lionel did this at least into the 1970s or 80s for example. I think Athearn did that for a long time too.
Yes, the GP9 seems to have been produced with two 36" fans and single 48" fans. I think the dynamic brake fan went from 36" to 48" between the GP7 and GP9 models just like they did for the F7 to F9. From track side, the louvers were a means of identifying.
riogrande5761 Yes, the GP9 seems to have been produced with two 36" fans and single 48" fans. I think the dynamic brake fan went from 36" to 48" between the GP7 and GP9 models just like they did for the F7 to F9. From track side, the louvers were a means of identifying.
The switch to the single 48" fans from the paired 36" fans occurred quite late in the GP9 production, at least in Canada. Similarly, I believe later F7s and GP7s had the larger dynamic brake fan when so equipped.
Upgrading locomotive design is often incremental. Deciding when to give the evolving product a new model designation can at times be somewhat arbitrary by the marketing department. Often the most significant improvements are internal. Modelers are primarily concerned with the cosmetic variations on the outside carbody.
John
cx500The switch to the single 48" fans from the paired 36" fans occurred quite late in the GP9 production, at least in Canada. Similarly, I believe later F7s and GP7s had the larger dynamic brake fan when so equipped. Upgrading locomotive design is often incremental. Deciding when to give the evolving product a new model designation can at times be somewhat arbitrary by the marketing department. Often the most significant improvements are internal. Modelers are primarily concerned with the cosmetic variations on the outside carbody. John
Dontcha know it. Regarding F7's, I can certainly cite examples with the D&RGW. Rio Grandes F7's went though a couple of notable changes between 1949 and 1952 when most of them were purchased. Most of the earlier F7's, some times referred to as phase I had horizontal louvers, air grills and 36-inch DB fans. The last batch of F7's purchased, some refer to as phase II had 48-inch DB fans, vertical slit louvers and Farr air grills. These were part of ongoing changes made by EMD and noted by rail fans. As you noted, there were some internal changes and other minor external changes, such as square or round corner cab doors, and later on the roof overhang was apparently eliminated late in the "phase II" production. D&RGW's "phase II" F7's had the roof overhang but other roads received them without.
The phase designations, according to literature I've seen were "coined" by rail fans and not the locomotive manufacturer. Those include things like F3 phase 1,2,3 & 4 and F7 phase 1 and 2, to refer to groupings of those incremental changes. Being that this is a model RR forum, yes we are concerned with external variations.
As for GP9's, I recall that Proto 2000 offered them with the paired 36" fans and the single 48" fans, which was nice to cover earlier and later GP9's. In the case of my fav RR, D&RGW, I believe their GP9's had the paired 36" fans.
EMD (Every Model Different) liked to make changes, or re-use parts.
CNW had late-production GP9s, and GP18s, with reused 36" fans from retired F-units.
Some early production GP9s (MILW for sure) had GP7-style cast handrail stanchions.
The louver by the compressor room is pretty reliable for telling between a GP7 or GP9. Most of the rest or the louver locations underwent changes throughout the GP9 run, and if a road had GP7s, most of the doors interchanged, so many variations could be found after a few years and trips to the shops.
I keep hoping for Walthers-Proto to release late-model GP9s in MILW, the 280-330 batch. Might be the largest group of engines on the MILW that didn't get renumbered.
Mike WSOR engineer | HO scale since 1988 | Visit our club www.WCGandyDancers.com
Thank's for the replies. On the post about the "GP9 frame and GP7 horns", that was a real embarrassment to the railroading world. Anyway, the unit IS indded a GP9 that was rebuilt out of a GP7 and the horns were never replaced, giving the unit a GP7 with dynamic brakes look. Either way, thanks for replying.
B30
Jim,The GP9 with the 48" fans was phase 3 GP9s that shared the same body as the GP18 with minor hood and grill differences.
The best way to tell a GP7 was by the 3 louvers under the cab and the number of louvers on the hood.
If one has keen hearing the 1500 hp 567B had a different chant then the 567C found in the GP9..
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
Back when the GP9 was new technology, there was a comment in Trains to the effect that the only way to be sure if a particular loco was a GP7 or GP9 was to look at the data plate.
Thanks to expedients during shopping and continuous upgrading by EMD (in manufactured specs) and the owners, I seriously doubt if you could find two identical locomotives in a given order after a few years service.
Chuck (Modeling Central Japan in September, 1964 - EMD, Nan des' ka?)
tomikawaTT Back when the GP9 was new technology, there was a comment in Trains to the effect that the only way to be sure if a particular loco was a GP7 or GP9 was to look at the data plate. Thanks to expedients during shopping and continuous upgrading by EMD (in manufactured specs) and the owners, I seriously doubt if you could find two identical locomotives in a given order after a few years service. Chuck (Modeling Central Japan in September, 1964 - EMD, Nan des' ka?)
Sounds like another old time Trains miss up..Most data plates was removed either by the railroad shop or "railfans"..Remember that old and very wrong saying: "If it has no DBs then its a GP7..If it has DBs then its a GP9. If it was only that simple to tell the difference between the GP7/9...
Actually most GP7/9s had the same appearance regardless of railroad except for the phase 3 GP9 with low hoods ordered by SP and the low hoods ordered by Philip-Dodge.
Gonna be a schmaut-butt here, but on the GPs I'm around this week, the GP7 has GP7 printed on the cab.
the GP9 used to, until someone drenched it in almost Wabash paint prior to the muesum's ownership. I do see a lot of modern locos with what it is printed ont eh side too.
-Morgan
IIRC, there was a mention that GP 7 and 9 can be recognised by the class lights on top of both hoods - or is this right only for SD counterparts? Also, I think the low skirting between trucks was removed on the GP9.
I have four P2K Geeps 7 and 9; #3400 of the B&O is passenger engine - it has "torpedo tubes" on roof and steam generator. Those early Geeps are my favourite EMD engines.
Thommo IIRC, there was a mention that GP 7 and 9 can be recognised by the class lights on top of both hoods - or is this right only for SD counterparts? Also, I think the low skirting between trucks was removed on the GP9.
No. All engines back then had class lights. The feature is totally the same on GP7, GP9, GP18s, SD7s, SD9s, etc. You can't use that to tell anything apart.
As stated before, the main visual difference (which is important to the modeller) between a GP7 and a GP9 is the louver locations on the long hood.
The main mechanical difference (which is important to the real railroad) is 1500HP vs. 1750HP.
Chris van der Heide
My Algoma Central Railway Modeling Blog
Not true as far as SD7's and SD9's go.
The SD7 class lights were centered over the number boards while the SD9 class lights were above the outboard edge of the number boards.
SP SD7: http://www.railpictures.net/viewphoto.php?id=324686&nseq=9
SP SD9: http://www.hankstruckpictures.com/pix/rail/sp/sp4402_canby_oregon_80s2.jpg
Check out other roads.
D&RGW SD7: http://www.railpictures.net/viewphoto.php?id=352755&nseq=4
D&RGW SD9: http://www.drgw.net/gallery/DRGW5308/drgw_5308_pueblo_co_unknown_000
Andre
Andre, this is exactly what I tried to say, thanks!
As for my Proto 2000 GP7 and GP9, there are no differences in class lights on the models.
andrechapelonNot true as far as SD7's and SD9's go. The SD7 class lights were centered over the number boards while the SD9 class lights were above the outboard edge of the number boards.
OK, fair enough. None of the roads I follow ever had anything remotely resembling an SD7. :-)
Every early GP I've ever seen from the GP7 to GP20 has had the class lights out at the sides the same as the SD9. The SD7 arrangement is unique.