GG1

[TH&B]

I heard another rule about the pentograph, that during freezing rain and sleet both graphs must be up so the leading one cleans the wire.

[Anonymous]

QUOTE: Originally posted by jchnhtfd


It is very rare to have both pans up, for the reasons given above. You simply don't need them. That being said, one of the more intriguing problems with high speed electric 'engines' (such as the Acela, or even more, the European high speed trains) is keeping the pantograph in firm enough contact with the overhead to transmit the current. I recall an engineering demonstration run of a TGV, some years ago now, at night. The section of line used has a slight imperfection (you couldn't see it by eye, but it was there!) in the overhead -- and the shower of sparks which resulted when the pantograph it that at about 200 mph could be seen for miles.

I see arcing on the NEC everyday. There are a few high spots (a guess) on the NEC just south of the Wilmington Station. Do the pans adjust at all? Are they set at a fixed height?

[jchnhtfd]

You all know I'm a GG-1 fan... so you could expect to see me here, eh? Technically the GG-1's traction motors are what is known as 'universal' motors (so are all but the most recent diesel-electrics). They could, in principle, run just as well on DC as they could on AC. What couldn't, and why they were an AC only 'engine', is the transformer system which controlled the voltage applied to the traction motors, and thus the torque (and speed) at which they would run. Transformers can only work on AC current. 440cuin is quite right -- the traction motors were only on the drivers (total of 6) and used a quill drive, which is a most ingenious way to fit a big traction motor into a relatively small space, and keep it on the frame rather than having its weight on the axle.

It is very rare to have both pans up, for the reasons given above. You simply don't need them. That being said, one of the more intriguing problems with high speed electric 'engines' (such as the Acela, or even more, the European high speed trains) is keeping the pantograph in firm enough contact with the overhead to transmit the current. I recall an engineering demonstration run of a TGV, some years ago now, at night. The section of line used has a slight imperfection (you couldn't see it by eye, but it was there!) in the overhead -- and the shower of sparks which resulted when the pantograph it that at about 200 mph could be seen for miles.

[TH&B]

GG1 had no motors in the pilot trucks. True the AC motors on a GG1 had less low speed tork than DC motors but once at speed they where more powerfull then DC hence an exellent passenger engine (even a heavy passenger train is not a heavy train compared to frieghts). A GG1 could keep a very heavy freight moving but if it got stopped on a grade by a block signal on the busy PRR it would often not get started and needed helpers, and that was how the diesel electrics or E44 were better for freight. But on passenger trains a G could out perform lashups of all the great passenger diesels wich were all more modern then the GG1. The NH EP-4 had sleeve bearings I believe, where the GG1 had roler bearings, basicaly an improved EP-4.
I think the GG1 is one of the greatest engines ever especialy for its time (timeless that is)

[Anonymous]

Well, I don't know much about GG1s, but since its willow's fav, here ya go:

[daveklepper]

The GG1 had all axels powered, including the front and rear four-wheel trucks, so you had a total of ten motors as compared with six for the E-60's and four for the AEM7's. I'm unsure of the exact horsepower or KW or amperage ratings, but I syspect the four motors on the two four-wheel trucks were about the same rating as the typical modern diesel-electrics motor, or about the same as each of the six on an E-60, but the six on the twelve "drive wheels", larger diameter, were probably considerably larger and obviously had larger cooling surfaces than the six under the E-60. So, with a lot of powered wheels, and all the weight providing adhesion for traction, and a very efficient springing system that kept slippage down without much in the way of sophisticated anti-slip control, you had a winner . Remember that this was a locomotive that could handle a passenger train at sustained 100mph speeds and still also hall a 75-100-car freight . I would say it was equivalent to three E-6 2000 HP diesels both in terms of speed and pulling power. I'm disscussing the 100mph geared variety, the "freight" GG1's were geared for 90 mph top speed. Yet, all in all it really wasn't terrifically different than the New Haven's EP-4's! The GG1's finast hour in my book is when they took over the ailing Metroliner MU cars that could not keep the schedule under their own power and maintained Metroliner schedules pulling the Metroliner mu cars, motors and all, cas trail cars. Dave Klepper

[oltmannd]

QUOTE: Originally posted by CSSHEGEWISCH

Regarding the above posting, is it possible that the GG1 could perform said feat and later locomotives could not because the GG1 had AC traction motors and all later locomotives were rectifiers with DC traction motors? One of the purported advantages of AC motors is that they aren't restricted by short-time ratings.

GG1s didn't have the same kind of AC motors as the new diesels do. They had motors with brushes in them and were regulated by varying the voltage to them. The low speed torque of these motors isn't great - in fact, it isn't as good as a series wound DC traction motor. The rectifier electric locos (e.g. NH EP5s, E33s, E44s) were an improvement over the AC traction of the P5s, GG1s et. al.

The AC motors on the new diesels are squirrel cage and are controlled by varying the frequency to them. Something that just wasn't technologically feasible before the mid 1980s.

[CSSHEGEWISCH]

Regarding the above posting, is it possible that the GG1 could perform said feat and later locomotives could not because the GG1 had AC traction motors and all later locomotives were rectifiers with DC traction motors? One of the purported advantages of AC motors is that they aren't restricted by short-time ratings.

[daveklepper]

Two correct reasons. Again, if ever (the Eternal forbid) the rear pantograph was damaged, somehow the train could proceed with the front pantograph. If the front pantograph had been used and then damaged, then both would probably be out of action. The same is true today on electrics with two pantographs, and this is true in Europe and Japan as well. A comment I made on the E60 discussion bares repeating. As Ed Hungerford commented in a TRAINS column some 50 years ago, during the heavy traffic WWII period, if the Silver Meteor or East Coast Champion or Southerner, came into Washington Union late to miss its slot in the corridor, the next hourly 3:55 scheduled end-point time New York express would be loaded on the lower level after backed down on top of the streamliner, and the whole 24, or 26, or 28 car train would run on the schedule of the DC-NY express and arrive on time in Penn Station NY (on time for the express, and the train from the south would not be any later!). As a ten-15-year old traveler I witnessed this procedure regularly. Nothing since the GG1 could do this! Dave Klepper

[espeefoamer]

In case the pantograph gets hung up in the catenary.If the front pan was raised,the rear pan would be torn off as it passed under the front one.
With the rear pan raised,the train could be towed beond the damaged catenary, and continue with the front pantograph raised.

[kenneo]

Stabilty. When the track wants to turn, the locomotive doesn't. So the front of the locomotive will dip away from the curve (just like you car will in a tight turn) while the rear of the locomotive will do so much less. By using the rear pantograph, the wire and the locomotive stay in better contact and there is much less wear on the wire and the pantograph.

The lead pantograph is normally used only if there is extra need for electrical contact or as an ice breaker in the winter.

[Anonymous]

Ive been wondering about that for a while too. And why is it almost always the rear pan?

[marxalot]

Howdy. Just got done reading the book : The Remarkable GG1 by Zimmerman.
My question is: It appears from most of the photos in the book that the "rear" pan is the one raised to get power most of the time. Was there a reason/rule for this?
There may be one photo with both pans raised but that was in a yard. Just wondering..... That is my favorite locomotive.