US Hobbies GP-7

[R.K. Maroon]

I don't know about you guys but it seems like we could use a model to look at here. I picked up a pair of US Hobbies GP-7s sometime ago that were setup for outside third rail. I decided to take a peek at what I was facing on the conversion to two-rail. Here is the unit with shell removed:



There is a lot to talk about here:

1. Compared to the Kemtron GPs, I was pleasantly surprised to discover that the handrail stayed with the shell. Excellent chassis-shell design and construction. Anybody know if this was original or a modeler's rebuild? The whole chassis looks scratched to me. The truck gearsets are All Nation (or some knockoff thereof).

2. Note the use of spring terminals on the headlight wiring to make it easy to remove the shell. Not pretty but elegant in its simplicity and ease of use.

Now a closeup:



3. Note the 0.04 MFD bi-polar capacitor in series with each headlight. My guess is that this is an attempt to reduce flicker. I am not interested enough in this to do a true circuit analysis or field trials, but I have my doubts as to the effectiveness of this approach. Wayne may wish to dive in with a transient analysis (I want to say "phaser diagram" because it sounds cooler, but my recollection is that those are for steady-state analysis). Wayne, the resistance of the light bulb when lit is about ten ohms (more at higher track voltages).

4. The gear tower is brass. Never seen that before. The machining is a little rough so again I am thinking scratchbuilt. The ratio in the tower is 2:1 (motor to output). The axle gearsets are 8:1, so that is 16:1 overall. This thing just crawls along (which warms my little "two rail is not Lionel" heart to no end).

5. This thing has the largest open-frame PM motor I have ever seen in an O-scale model. Note that the modeler had to shave off the side of the engineer, seen in the top left of the photo, to squeeze him in next to the motor.

Milwaukee Road would sometimes lash up a half-dozen or more road switchers for drag freights, and one of my long-term projects is to model such a train. With that big motor, low gear ratio, and those lead weights, this one (and its brother) will fit the bill nicely. I have an RS-3 and RSD-5 in orange and black too. They need some drive work anyway so I will make a point of lowering the gear ratio while am at it. Now I just need an FM unit to complete the set. And a ten-amp power supply to run the whole thing. Mmmm, if I close my eyes I can smell the oil-and-ozone already.

Jim

(edited title)

[R.K. Maroon]

I thought about it a while and have another theory on those capacitors. I think they may be part of a constant lighting setup. Maybe Wayne (or others) can guess my thinking here. Phaser analysis might actually work here after all!

[rrjjf]

RK,

Your post is very interesting to me. Last Saturday at the Maurer auction in PA I picked up a US Hobbies GP-7. My model has a Dynamic Brake casting and the small box ahead of the cab on the deck is not there. The model has never been painted. Someone has installed a Pittman 8000 can motor to replace the original open frame motor. The gear tower and gearboxes are cast Zamac and appear to be in perfect condition. After lubrication, the loco took off pulling a 20+ car freight train drawing less than 1 amp. Trucks appear to be nickle plated brass castings with good detail. Included with the model was a small bag of detail parts, windshield wipers, various horns and a bell to be installed. I will eventually detail this model as Western Maryland No. 20. The dynamic brake casting will go and a small step box will be added ahead of the cab. Max Gray originally offered this model as well as US Hobbies and it looks like they offered it in slightly different configurations.

The only electronics found in my model was a disconnected Selenium rectifier. I am very pleased with this model.

Joe Foehrkolb

[aww]

Pretty cool! Looks like he knew what he was doing. Maybe a picture of the underside?

I'm always interested in drive systems. My Squaw Creek Penn Erie project is coming along but I am going to change the drive from my original plan. That was two motors, one for each truck power going through PSC transfer cases to USH gearboxes mounted in your (Marroon) trucks. I got it running but didn't like it. This is the second time I have tried two motors and the first one didn't work either. One truck sometimes starts before the other, also the transfer cases produce some noise, vibration in the body. I'm going to a simpler setup with a large motor in the middle, like a USH Hobbies. I think with flywheels on the motor, this engine is pretty long and there is space.

It's not painted yet so I can still work on it, and still have some details on the body.

Allan

[Jay Criswell]

I've owned quite a few of these over the years. The early Max Gray models had a non-blackened brass tower case. Later, along with the trucks, frame, fuel tank, etc., they blackened them. Following that they went with the Zmak cast tower. Some run okay, some run really lousy. All can benefit from a generous dose of fine tuning.

My biggest complaint was the fact they called the model without dynamics a GP7 and then added the dynamics and called it a GP7. GP9s didn't have louvers on all three battery box doors (three on each side below the cab). Other louver configurations changed between the two EMD products but I could live with that because I could never remember which is correct for a particular model. The louvers on the battery box lids just bugged me. Kind of like Bob and the bottom of boilers being gutted to make room for drive-lines and gearboxes on a steam engine.

I also realize that I'm probably the only person around that finds the inaccuracy troubling.

I will say, despite the noise generated by the design used in these models, they are stout. Good luck and have fun. If you need any parts let me know, I may be able to assist.

Jay

[R.K. Maroon]

Jay, you are definitely not the only one to have a bone to pick on this GP7/GP9 issues. Here is the straight skinny for those inquiring minds that may want to know:

According to the Max Gray Spotters Guide, MG only offered the GP7:



Here is the US Hobbies version of the GP7:



The biggest difference I see is the MG has the winterization hatch, though there are also differences in horn placement, cab windows, and those two interesting "straps" (batton strips?) running vertically on the sides of the MG unit (The USH unit may have them too but they seem more prominent on the MG). Here's mine:



This doesn't exactly match either, but with the winterization hatch and the straps I will guess MG. Jay's information regarding the non-finished brass gear tower on the MG is also good evidence.

Here is the offending USH GP-9, which Jay correctly asserts is a GP-7 with dynamic brakes:



Here is my other unit. It has the dynamic brake housing so my first guess is USH, but I will have to inspect more closely to be sure:



What I find particularly interesting is that US Hobbies was owned by Levon Kemalyan, who also owned Kemtron. So Levon was competing against himself on GPs. Interestingly, as best I can tell, Levon never marketing the Kemtron GP-7 as a GP-9:





Finally, here is a photo from a US Hobbies newsletter showing the GP chassis:



That's a good match, so my chassis is not scratchbuilt but more-or-less as delivered.

Photos of the underside for Allan next.
Jim

[bob turner]

By golly, I think I have one of these. My friend Bud's daughter gave me a T&P. I should pull it apart (and fix the handrails).

I also realize that I'm probably the only person around that finds the inaccuracy troubling

No - this sort of thing drives the 3-rail scale folks absolutely nuts.

[bob turner]

Is this photo good enough to identify it?

[Jay Criswell]

Bob, et al,

Another issue that causes consternation for some modelers, The MG vents (on top of the locos) were open (castings or coinings, I believe) and the USH were not (stampings). That means the MGs are preferred over the USHs by some folks.

In other words, you could see through the MG vents but not the USH. Done to save money I suspect.

Jay

[R.K. Maroon]

Is this photo good enough to identify it?

Between the lack of winterization hatch and the location of the horn, I would guess USH GP-7. But just to be sure, I think you should send this one to me. I will return it someday, I promise (no.....really).

Jim

[bob turner]

Will you re-solder and repaint?

[R.K. Maroon]

I would resolder the stanchions for sure. If by "repaint" you mean "touch-up", then again, for sure (though matching the "swamp holly orange" might be a challenge). If you mean "strip and re-paint from bare brass", then, no, I have too many models on the tracks outside the paint shop as it is. The paint here looks serviceable to me, but maybe eyeball inspection shows it needs help. I do find the T&P schemes attractive (mild understatement). Unfortunately, my brother and I arrived on the Texas scene long after this scheme was gone. There also was a short-lived blue and white scheme which was also gone by the time I arrived as a nine-year-old in 1967. I only remember the Jenks Blue and the MoPac lettering. Pete was older and may remember otherwise. To my surprise, Microscale offered GP decals for the blue and white scheme:

https://www.flickr.com/photos/joemcmillan118/13902798864/in/photostream/

I have a cast bronze GP that will get this scheme if and when it floats to the top of the queue.

[rogruth]

Jim,

Thanks for the T&P blue and white scheme.
I don't think that I have seen it in color before.
I thought that it was a black or a dark blue and white scheme.

[DeBruin]

It is neat looking isn't it Roger?
They had a version like it for F units as well distinctly different then the Eagle passenger scheme on the E units and Psgr F's.
Apparently parent MP's HQ eventually grew to not appreciate the T&P's independent streak, nixing even this blue and white version as well as the earlier "Swamp Holly" Orange and black scheme, even making the road discard it's diamond herald in favor of the MP buzz saw and a sea of "Jenks" blue dip.
(sigh)

[R.K. Maroon]

I was curious about Swamp Holly Orange. Here is what I learned:

1. Swamp Holly is a rather rare plant found in south Dixieland from Florida to East Texas. So far, I have not found a reference as to which part is orange. The berries are red from the photos I have found so far, so one would assume the blossoms are orange (no, not the same as the orange blossoms of special fame). Odd that an uncommon regional plant would have a color named after it.

2. Swamp Holly Orange was a color offered by DuPont as early as 1929. Maybe the swamp holly was more common then.

3. Swamp Holly Orange was chosen by a national truck lines for all its trucks for safety reasons as studies showed it was most visible of all colors DuPont offered at the time (again, 1929). This trucking company was Yellow Freight Lines. So Yellow Freight has orange trucks. Hmmm...OK. This one may be way off, but I would never have said that the color of Yellow Freight trucks is the same as the T&P scheme. But I only have photos to go by -- very unreliable.

4. The Yellow Freight company was started by the same guys who started Yellow Cab. These guys let a national fortune slip through their fingers by not registering "Yellow Cab" as a national trade mark. But they got a second chance with Yellow Freight and from the evidence it appears they did not screw that one up.

And now you know the rest of the story
Paul H.