Need help with locomotive dimensions

[DKS]

I posted this question on the Trains board a couple of weeks ago in an existing thread about the GP7 vs. the GP9, and there was no response. So, hopefully someone here may have the answer. The published specifications on the GP7 and GP9 indicate a three-inch difference in overall length (55'-11" vs. 56'-2") as measured from coupler face to coupler face. Three questions:

1. What consitutes the difference in overall length?

2. Is there a difference between the two with respect to the pilot face to pilot face length, or the length of the hood?

3. What are the pilot face to pilot face length(s) and the hood length(s)?

Thanks much in advance.

[daniel_leavitt2000]

Didn't the pI GP7 feature an angled pilot face where the GP9 was flat? They could also be meaturing the pilot face of the GP9 at the pilot mounted MU recepticles where the early GP7s had them mounted up near the walkway.

[up1950s]

3 battery vents on the 7 and 1 on the 9 below the cab on the wide sill area forward toward the short hood , is the big spotting feature .

[Chris333]

In the Dec 02 MR there is a write up on GP9's with 3 different drawings. The overall length th is measured from the center of the coupler. The SP low nose GP9 is 56'2" and the high hood NYC GP9 is 55'11"

Easier to scan than type:

[DKS]

Thanks guys, I can see I needed to be more specific with my question. I already have all of the spotting differences down; I was just looking for reason why they are different lengths, when it seems that they are otherwise identical (save for battery vents, fans, etc.). I'm also hoping someone can come up with the overall hood length and pilot-to-pilot dimension.

[Chris333]

I think a GP7 and old GP9 have the same length, it is newer GP9's that are 3" longer.

I tried to check the drawings with a scale rule, but a scale 3" is hard to find.

[DKS]

I think a GP7 and old GP9 have the same length, it is newer GP9's that are 3" longer.

I tried to check the drawings with a scale rule, but a scale 3" is hard to find.

Thanks, Chris--I had a sneaking suspicion that this might be the case. The dimensions I've found were never phase-specific, and I wondered if the extra 3 inches didn't show up until later. It'd just be nice to confirm this somehow.

[Chris333]

A Erie GP7:
http://www.rr-fallenflags.org/el/loco/edb-37d.gif
http://www.rr-fallenflags.org/el/loco/edb-38d.gif
http://www.rr-fallenflags.org/el/loco/edb-39d.gif
Erie GP7's were built in 1950 and 1952.
A Erie GP9:
http://www.rr-fallenflags.org/el/loco/edb-38ad.gif
Erie GP9's were built in 1956.

Shows a difference from the pilot face to the coupler. GP7 is 23-1/2" GP9 is 25".  It could just be different draft gear?

[Chris333]

Now I don't feel so bad with the ruler. It was 1-1/2"at each end I couldn't find not a whole 3" 

[3rdrail]

I don't know, but I suspect it is a 1.5" difference in the draft gear travel. After all, it is pulling face to pulling face.

[DKS]

I don't know, but I suspect it is a 1.5" difference in the draft gear travel. After all, it is pulling face to pulling face.

I was just about to post the very same remark, when yours just popped up. Great minds!

Thanks very much, Chris, for these drawings (and your efforts to measure a scale 1.5"!), and to everyone else for all of your help.