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.
Ive been wondering about that for a while too. And why is it almost always the rear pan?
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.
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.
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
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.
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
Well, I don’t know much about GG1s, but since its willow’s fav, here ya go:
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)
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.
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?
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.
There is a lot of vertical travel available in a raised pantograph. Pantographs have springs which are supposed[:)] to hold them against the overhead, together with (usually) some air pressure (some designs use motors to raise or lower). Older designs had just the springs and air – and depended (like old cars with leaf springs!) on friction in the joints to provide some damping. Newer designs, and all high speed designs, have what amount to shock absorbers in the linkage, to keep them from bouncing around – and off the overhead[:(]. Where things get interesting is that the overhead deflects with the pressure of the pan on it…[:D] It is pushed up by the pan, so, naturally, it deflects down a bit in front and in back[8)]. Depending on the speed of the train, and the design of the overhead, and the tension on the overhead, it is quite possible to get the whole overhead to produce a nice wave[:o)] – and if the timing is wrong, the pan may be unable to rise fast enough to keep up with the wave – at whi
Jamie,
Thanks for the good info. I can easily see the pans on the Amtrak Loco. It thought they had springs. This is happening at slow speeds as trains are exiting and entering the station from the south, about 500 feet from the start of the platforms. It happens at the same locations. It real cool when its dark out!!
Arcing — are there track switches at that location? I would venture that there are, and the pantographs will arc against the wire at such locations as they pass by the insulators.
GG1’s wheel arrangement is 4-C+C-4. The locomotive nomenclature (GG) comes from the PRR nomenclature for a ten-wheeler - Class G. As far as the PRR was concerned, what you had was 2 10-wheelers back to back. The 4-C on each end was a span bolster with an articulated joint and the car body rode on top of the span bolsters. That is where the “+” comes in.
… _____ + ______
Looks something like this ooOOO + OOOoo. The carbody sits on top of the lines.
Hauling ability - Two Points – First Point - The comments above about the motors and such are esentially correct. What also needs to be factored in is the fact the power source is not carried on-board, but is land based with a (supposed) unlimited ability to put juice to the locomotive. What is being said is, a 4,000 HP (GG1’s were rated at 4000HP) diesel can only produce 4,000 HP. Period. I was told once, but have since forgotten, but my memory says the GG1 could, on a short term basis, produce between 8,000 and 12,000 HP which is one of the reasons it could haul a 28 car express and still maintain the schedule. The power station would just keep producing and the locomotive would just keep on using - almost without limit. It would probably take something 6 E-9’s to do the same job but at a slower speed - probably 80 MPH. This ability of wire over diesel is why it is still in use in the NEC.
Second Point - Gearing. Gearing. Gearing. The slower you gear for, the more an electric motor will haul. The faster, it will haul less, be more slippery and race with the wind. These two reasons are why a “normal” passenger consist for a streamliner was usually no more than 22 cars and 4 E7, E8 or E9’s. With a train such as a “City” geared for 110 MPH, it would take 4 E9’s to keep a 100 MPH sche
I stand corrected on the pilot truck GG1 motors, yet I do remember reading something about this in an authoritative publication many years ago. Perhaps it was an experimental installation? Can anyone enlighten me? Regarding making up time. Remember when both the Silver Meteor and the East Coast Champion had 24 hours schedules Miami - NY? The ACL had a double-track block signalled line and the SAL a single-track CTC (mostly) line. One day I boarded the northbound Silver Meteor at Jacksonville to ride coach to Southern Pines, NC. Three E’s on the head-end, forget whether E7’s or E8’s. Rode the rear round-end observation (coach passengers were allowed to do so on the SAL). One of the secondary trains had been dropped from the schedule, and its express and mail work was transferred to the streamliner, but the schedule had not yet been lengthened from 24 hours. (It was at the next timetable change, and the ACL did the same.) On the straight alignment north of Jacksonville I clocked the mileposts a mile each 36 seconds. That’s 100 mph. The brakeman was sitting on the other rear-facing seat. I turned to him and said: “We are going 100 miles per hour!” He replied" “The ICC mandated speed limit on this line is 79 miles per hour, and that is as fast as we are going.” I: “But I’m timing the mileposts at a mile each 36 seconds, and that is 100 miles per hour.” He simply repeated the same sentence over again. I shut up. I didn’t tell anyone, either. At that time the running time for the Silver Meteor was 3:45 from Washington to New York. The regular hourly expresses were 3:55 (including if memory is correct the Colonel and Senator from Boston); the Morning and Afternoon Congressional were 3:25 or 3:30. I don’t remember what the running time of the East Coast and West Coast Champions were, and maybe someone can remind me. Washington-NY was GG1 territory, other than the MP54 mu locals (and lots of them), all passenger service was with GG1s. Florida trains, trains to the west diverging a Zoo i
Hi Dave, hi everyone!
No, I won’t pretend I could enlighten you or even give you any hard facts, but I think I remember reading somewhere that each of the six driving axles of a GG1 had two traction motors, so there were actually a total of 12 traction motors in each GG1.
Anyway, they were gorgeous machines. [bow]
Have fun!
Oliver
Perhaps what you are thinking of is the P5B that the Pennsy made. They took one of the P5A locomotives and added motors to the leading and trailing trucks. Thus turning a 4-C-4 into a B-C-B. It was more powerful than the P5A but not enough to bother repeating.
Minor corrections on wheel arrangement: axles are counted, numbers are unpowered, letters are powered, thus:
GG1 - 2-C+C-2
P5A - 2-C-2, P5B - B-C-B
Little Joe - 2-D+D-2 (same on a Centipede)
Bi-Polar - 1-B+D+D+B-1
W-1 - B-D-D-B