GG-1 vs AEM-7

I know previous topics touched what it would take for a GG-1 to be put into running condition etc, but I would like to know what a match-up would be like if you took a new"off the line" GG-1 and put it against a new AEM-7 (or whatever electric Amtrak has these days). What would be the "tale of the tape?" Include all categories!!!

Since you will never see a new GG-1 and will never see old GG-1 back under power this subject is kind of off the wall.
you want to see a new GG-1 ?? its called a HHP-8

It was a hypothetical question Dutch. Side by side comparison of the GG1 and AEM7, not an HHP-8

The Stats:

GG-1
Weight: 238.5 tons
Power: 4620 HP
Technology: Universal motors and tap changers
Top speed: 100 MPH (passenger gearing)
Build date: 1930s to 1940s

AEM-7
Weight: 101 tons
Power: 7000 HP
Technology: DC motors
Top speed: 125 MPH
Build date: 1970s to 1980s

Speaking from an electrical perspective:
The G's were a beast, and the toasters were the ballerina - The traction motors on the G were probably twice the size of the AEM7's, and were likely of "wound-rotor" construction, a typical method for american electric motors until the mid-1980's. They operated a quill-drive system to engage the wheels - I'm still not totally sure how this worked, but it involves engaging the spokes rather than a bull-gear on the axle. The toasters have modern traction motors with conventional engagement to the axle, through a bull-gear. They also have thyristors, which are intelligent controllers (sorta like inverters), as opposed to the Massive NEMA-standard contactors, probably 6" square or more, in the G. Today, a moderate sized NEMA contactor costs $300+.

From a structural standpoint:
The G was built in an era when structural and metalurgical engineering were very primitive. Carbon steel was still sometimes created by hand-adding coal to the molten iron at the last part of the Open-Hearth process. How's that for measurability and uniformity? The answer to the problem raised above, was to just add more [steel]. As you can see, the G frame is absolutely goliath in proportion, and the wheel-pattern is related to a steamer with lead trucks for stability. The toaster has a precisely engineered structure, built of A36 steel (and comparable iron in castings), much more modern than whatever was used at the time - likely A20 or A8. (A-number being a strength rating in kips I believe)

Couple the modern control system with the modern structure, and you've got a real lightweight ballerina. While I don't know much about transformers, it seems the AEM7 xformer is a powerful one, making for the most versatile engine since the GG1. So although while the GG1 and AEM7 are't alike physically, their exceptional design, power, and versatility for their era makes them alike in being the best of breed. And until we find out if the HHP is a junker or just a teething product range, I'll feel confident in making that statement.

Lucius Kwok wrote:The Stats:

GG-1
Weight: 238.5 tons
Power: 4620 HP
Technology: Universal motors and tap changers
Top speed: 100 MPH (passenger gearing)
Build date: 1930s to 1940s

AEM-7
Weight: 101 tons
Power: 7000 HP
Technology: DC motors
Top speed: 125 MPH
Build date: 1970s to 1980s

AEM-7AC rebuild features AC traction motors.

The ALP-46, which Amtrak used on the Clockers prior to their cancellation, is probably superior to both AEM-7AC and HHP-8.

Something on the order of a GG-1, built with modern technology (and engineer-friendly cabs), would probably outperform any of the minute "toasters", I suspect…

Aem7 dc models are actually de-rated to 5300hp. Supposedly, the
the original set-up had too much power at the wheels.
Aem7 ac models are rated at the full 7000hp.

DutchRailnut wrote:

Since you will never see a new GG-1 and will never see old GG-1 back under power this subject is kind of off the wall.

I respectfully disagree. There are no insurmountable mechanical, electrical or structural problems in any of the 4 or 5 best-preserved G's that would absolutely rule out eventual restoration and operation. Cost? Probably not cheap; but the technology and expertise to do it certainly exists. Everybody frets and moans about the G's PCB oil filled transformers. Get me the specifications, dimensions (...the original construction drawings or one of the actual transformers would be better) and a check, and there are at least 3 manufacturers who will deliver a superior, non-PCB replacement in less than a year.

amtrakhogger wrote:

Aem7 dc models are actually de-rated to 5300hp. Aem7 ac models are rated at the full 7000hp.

...and due to the power and current-limiting features of the electronic drives for the traction motors, I do not believe that you can get even one horsepower more than "rated". GG-1's were 4620hp continuous, but were rated 10,000hp "short-term", which was considered 30 minutes!

Lucius Kwok wrote:

AEM-7 top speed: 125 MPH
GG-1 top speed: 100 MPH (passenger gearing)

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.

Irish Chieftain wrote:

Something on the order of a GG-1, built with modern technology (and engineer-friendly cabs), would probably outperform any of the minute "toasters", I suspect…

Can you just imagine what kind of beast of a locomotive an updated GG-1 would be? I have; and I only wish I had the ability to write the check to make it happen; to see it happen would be the most amazing thing in my life.

You got about the same chance seeing a GG-1 run again as you have a
K-4 on the Broadway Limited again.
At least a few were saved, go get your jollies off looking at one on a
siding or in a museum someplace, the best place for them.
Noel Weaver

MODERATOR'S NOTE:

Thread is moved to General Discussion: Locomotives, Rolling Stock, and Equipment.

Okay, it's pretty tough to compare two technoligies that are four decades apart, but the laws of physics haven't changed.

Horsepower is all well and good, but it's TRACTIVE EFFORT that starts trains. With a weight of 477,000 lbs. and primitive wheelslip control, let's assume a factor of adhesion of 20% (older diesels are typically 25%). That gives a starting tractive effort of 95,400 lbs.

Contrast this with an AEM7 at 101 tons or 202,000 lbs. Figure a factor of adhesion of 35% for a rebuilt A/C unit, and you've got 70,700 lbs. Now you see why Amtrak uses two AEM7s on heavy trains (like the Florida trains).

Oh, and PRR Tech Fan, that's 155 lb. rail, not 151.

Actually, the PRR listed the GG-1 at about 70,000 lbs.

On paper, the ALP-46 or the HHP-8 should equal a GG-1.

In reality, in a 0-100 contest, any train the '46 or HHP-8 could start, it could outpull a GG-1 to 100 with. The GG-1's only peaked at around 8500HP and that was at about 70mph. The '8 or '46 can deliver darn near full HP from almost 0 to almost 100.

The GG-1 also didn't have all wheels powered. It DID have a much more massive transformer, though.

I concur with Noel that you won't ever see a GG1 run again. If there's some billionaire that really likes choo-choos, perhaps...but absent that, I doubt it.

Don't forget that you not only have to completely refurbish one, you have to convince someone to let you run it on their rails, which is likely going to be much more expensive than running a steam engine, due to te complexities of catenary.

I love GG-1's, and my dad and I once got a cab ride into NYC on one...so I'm partial to them...and I don't ever think you'll see it again.

Dave Becker

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 Brunswick Green, I've also heard it called "DGLE" for Dark Green Locomotive Enamel. I've not been able to tell it from black, either.

This is really an interesting discussion; I am not an expert by any means on this so I'm learning a lot.

Although this isn't what the thread is about, from a sentimental and perhaps aesthetic I don't think there is any comparison between the GG-1 and the AEM-7. Being a young railfan at the time, I had no clue how darn uncomfortable they were for crew members, either. But there will probably never be another Raymond Loewy again, and if there is I doubt that he'd be in the employ of North American railroad companies-- that's just not what the business is about anymore.

I agree that you'll never see a G under wires under its own power again, and I'm grateful that there was enough foresight to preserve a few for us to share. I was there for the debut of the restored 4935 and 4877 and I was there for the last run of the G as well. Those are all good memories.

And of course there are the models and of course I have one, with sound that is real enough to me!

Thanks for sharing, everyone...