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  • GG-1 vs AEM-7

  • General discussion about locomotives, rolling stock, and equipment
General discussion about locomotives, rolling stock, and equipment

Moderator: John_Perkowski

 #314079  by Tadman
 
I don't think the paint scheme determined gearing - I think the tuscan red g's were originally for Clocker or Congressional service, and the special paint job was to denote a somewhat more special level of service. I think Noel or GBN could likely shed some light on that. If I recall, only about 10 or 20 G's were in the tuscan red. It's also quite common to see DGLE G's on passenger runs. After 1960, I don't think anybody cared what color engine pulled which train.

Although I have an old Don Ball book, Portrait of the Rails, with a pic of a GG1 and two RS3's pulling the chalk point coal train. Neat pic.

 #314109  by BoilerBob
 
The "Cat Whiskers" and lettering were orginally real gold leaf too.

The quill is simply a tube around the axle below the motors (2 motors per axle) and supported by friction bearings. On one end of the quill is the quill gear with spring cups attached to the outboard side of the gear. These cups were made of very hard rubber (hockey puck type rubber). The cups pushed against a plate attached to the wheel. This was much gentler to the wheels and rails.

I have a picture of the quill, motors, bearings, etc. but I don't know how to get it on the forum screen for all to see.

 #314126  by pennsy
 
Yo Tadman,

Check out Pennsy Power I & II, by Stauffer for data confirmation.

And by the way, I haven't even scratched the surface on said data.

 #314182  by timz
 
PRRTechFan wrote:GG-1's were 4620hp continuous, but were rated 10,000hp "short-term", which was considered 30 minutes!
Considered by whom?
PRRTechFan wrote:In early testing for high-speed service, a specially geared GG-1 pulling 8 specially-sprung Pullman coaches was clocked at 151 mph through Princeton Junction on track 3, this stretch of which had been outfitted with constant-tension catenary and what would eventually become known as PRR "standard" 151# mainline rail.…
Who said?

 #314194  by Noel Weaver
 
pennsy wrote:Hi All,

Interesting question, and one that was brought up some time ago. I imagine there are those that might even suggest I was the one that started that thread. Memory fails me on that one. Possibly I did. At any rate let's see what we have to add;

Electric engines have a continuous horsepower rating and a short term overload horsepower rating. GG-1's have been known to deliver up to 10,000 hp for a few minutes. The 7,000 hp rating for the AEM-7 is of course short term. Continuous horsepower is similar to continuous HP for the GG-1, about 4200 hp. Still and all, a single GG-1 routinely hauled around 18 passenger cars, at speed, and the AEM-7 routinely hauled about half of that, about 8 cars, at speed. When you see 18 cars behind an AEM-7, you also see a second AEM-7 behind it. I have been in the cab of both engines, and needless to say, the AEM-7 is a comfort cab, really nice. The GG-1 must be compared to the cab of a steamer, in which case it is also really nice. If you compare the cabs of both engines together, the AEM-7 wins hands down. Difficult to make a GG-1 slip, not too hard for an AEM-7. Lots more weight on the drive axles for the GG-1.

Gearing: The GG-1's came in two colors for PRR. Tuscan Red and Brunswick Green. Brunswick Green was made by adding one gallon of bright green paint to a 55 gallon drum of black paint. Old PRR joke, but the Brunswick Green easily passed for black. The Tuscan Red GG-1's were used for passenger service, and geared for 120 mph. The Brunswick Green GG-1's were generally found on freights and were geared for 100 mph. When I rode the Congressional I usually caught the Tuscan Reds, especially on the Stainless Steel cars. The Brunswick Green engines were usually found on the old six axled heavyweights.

That is "nuff for now.
On the contrary, the GG-1's were quite slippery under certain conditions.
I was not out of the ordinary to experience wheel slipping on Hell Gate
Bridge, West Haven Hill or leaving a station with a big train.
I recall a couple of times going over Hell Gate Bridge westbound when I
really had to baby the engine to make the grade over the bridge. Never
had that problem with an AEM-7 or a New Haven 370 class either for that
matter.
I am not saying that the GG-1's were not a good engine but they had
their shortcomings and were not perfect.
Noel Weaver

 #314203  by pennsy
 
Hi Timz,

Considered by the temperature of the traction motors. The limiting factor for such overloads is the maximum temperature achieved by the traction motors before the circuit breakers cut out to protect the motors. And by the way, that amount of time, a guesstimate, is also based on the outside air temperature and wind speed. That is why electric engines are preferred in cold climates. They are most efficient in ice and snow. Huge heat sink to keep the traction motors relatively cool as they put out the tractive effor. By the way, by extension, you don't want electric engines operating in death valley type environments. You would have to provide refrigeration for each traction motor.

 #314210  by timz
 
So in zero weather a GG1 was good for ... maybe 20000 hp?

 #314261  by pennsy
 
Hi,

The testing cited earlier where the figure of 10,000 hp was calculated was well documented in the literature I referenced. To the best of my knowledge it was never carried any further than that.

The condition of the rails on the Hell Gate bridge causing the GG-1 he was driving to slip I find fascinating. First off, in those days the GG-1's never had anti-slip devices on board. The AEM-7 did. I would be most curious as to what were the weather conditions on those rails at that time. As a guess I would say that the rails were good and wet, possibly had a nice layer of ice on them, and in other words a fine situation for liberal use of the sanders. In my day, that bridge was New Haven territory and you would not find a GG-1 on those rails. The other option was that the train was a freighter and was hauling tonnage. I'll also venture a guess that there was more than one GG-1 on the point. By the way, I have seen. really long freights hauled by, believe it or not, FOUR GG-1's.

 #314294  by timz
 
pennsy wrote: The testing cited earlier where the figure of 10,000 hp was calculated was well documented in the literature I referenced.
Staufer, you mean? He mentions the 100-mph-in-64.5-seconds story, but there's no "well documented testing" anywhere in his books. That's no knock on the books-- that info just doesn't exist.

 #314331  by Typewriters
 
I am not entirely certain where the figure of 10,000 HP for the GG1 comes from, but information in Don Ball's book (written with E.T. Harley) on the Pennsylvania does give that figure and indicates that it was achieved during the competitive testing between it and the R1, ie the last set of Claymont tests. In PENNSY POWER II, Staufer mentions 9000 HP; Kirkland, in his book on Baldwin diesels mentions that the maximum speed achieved in the second round of tests was 115 MPH.

However, we do have a primary document that supports high overload figures for the GG1. A brochure in our collection put out by Westinghouse in 1948 summarizing the future of motive power has the following paragraph in its section on electric locomotives:

"The finest current examples of the a-c series motor locomotive are the Pensylvania GG1 and the New Haven EF-3. While they are nominally rated at 4800 continuous HP, each can deliver from 8000-9000 maximum hp, if occasion arises." In the rear of this brochure are tables and graphs; the stated maximum HP at the rail for the GG1 in this table is 8500.

Also, for what it's worth, the GG1 units modified for freight service were apparently regeared for a maximum speed of 90 MPH and had their (three) overloads (per unit) set at 2750 amps; the passenger units, geared for 100 MPH had the overloads set at 3000 amps (this from document PENN CENTRAL CT290 Electrical Operating Instructions, January 1973.)

Hope this helps.

-Will Davis

 #314345  by Nasadowsk
 
Electrics do just fine in hot weather, too. Yes, they like the cold. But motors of that size are common in industry, and in places where the air temperature routinely gets into the 100's. Heck, all nuclear plants have much larger motors, and PWRs have them in the containment, where temperatures are generally on the high side anyway.

The trick is a LOT of cooling air. The ASEA units that Amtrak uses these days were designed for Sweeden, thus they don't have huge transformers or enormous blowers. Well, when the outside air's cool, you don't need it. If they were designed in a desert area, they'd have gigantic blowers and gigantic transformers.

The E60s have run for years out in Arizona, and they do just fine...

By the way, the E60 also had circuitry to model the temperature rise in the propulsion system and limit power as a result. It actually could predict when the transformer was likely to overheat.

The GG-1 was likely the first large scale implementation of quill drive, which is seen everywhere today, though it was likely independently developed elsewhere. It's still common on European equipment.

As for the GG-1 being slippery, I can believe it. They couldn't get the kind of control today's stuff can get.

Ever hear an ALP-46 leaving a station. They can get remarkably agressive at wheelslip control - to the point that the screech drowns out the rest of the motor's noise.

 #314365  by PRRTechFan
 
NellieBly wrote:
Oh, and PRR Tech Fan, that's 155 lb. rail, not 151.
...you are, of course correct! I posted that very late at night; the numbers were starting to get blurry...

I previously wrote: In early testing for high-speed service, a specially geared GG-1 pulling 8 specially-sprung Pullman coaches was clocked at 151 mph through Princeton Junction...

Timz wrote:
Who said?


...I will try to find the photograph and newspaper article, and if I can find it, I'll post it...

 #314366  by Noel Weaver
 
On the GG-1's the motors from 4800 to 4886 inclusive were geared for 90
and 4887 to 4938 inclusive were geared for 100. There was a metal
plate welded to the frame next to the controller on each end of the 90
MPH engines so stating that they had 90 MPH gear.
The circuit breaker would trip at 3000 amps on the 100 MPH engines and
2750 amps on the 90 MPH engines.
Paint had nothing to do with the top speed in any case, indeed 4877 was
a 90 MPH engine red paint and all.
Noel Weaver

 #314559  by pennsy
 
Hi All,

Speed ???

Referring back to the Stauffer books; seems that the Enginemen were duty bound to maintain their schedule. Accordingly, some got caught putting the "pedal to the metal". Some of the Towermen would actually put a stopwatch on the passing trains and catch these zealous fellows. Of course they were disciplined afterwards. Speeds on such trains were often approaching 120 mph. Short bursts of speed, undoubtedly, but they did the job, and the trains arrived, "on time".

On the PBS film, on a journey across the USA, from Penn Station NYC to LAUS, the first leg of the trip, as reported by Ludovic Kennedy, was from NYC to Harrisbury via GG-1. This was the only phase of his cross country trip where he arrived "on time".

 #314600  by Nasadowsk
 
120 from a GG-1? I doubt it - that's a 20% overspeed on the TMs. That's enough to make them come apart, especially with the hit/miss alloys of the 30's.

In any case, the motors likely fell on their faces at those speeds anyway.

I could see 110, but 120? No.

FWIW, the Arrow II/III cars were set to cut power at around 103-105mph.