Alright you juice jacks...

Got another question. I've been reading a lot of books on the Milwaukee and it's electrifird lines and I have some pantograph questions. On their Little Joes, the front pan is up on each unit. On their boxcabs, only one pan is up, and it's on the front. Why the front pan? And I am guessing that the boxcabs have a bus bar or something like that to distribute the juice drawn off the cantenary. Is that so? And do the pans make an irritating, scraping noise as they slide along the wire, or is it not easily heard over the rest of the noises?

Yes, the power-cars distribute their gained power throughout the rest of the train.
Also, are you stating that each power-car has two pantographs? If so, that might be to improve traction; if you're pulling something, you want to have the forward drive-set delivering more power, so as to increase the grip on the tracks. If you were to have the back deliver the most traction, you wouldn't have a good grip on the front end. However, I don't know if that's the case with your entity. That's just my speculation on this problem.
Also, I've seen pantographs of that type, and they barely make any noise, except in the instance that the pantograph should touch the wire for the first time after some time of losing contact with them; the small area of contact at that precise moment, and the air in between them makes for some sparks, which only I seem to pay attention to!

BlackDog wrote: And do the pans make an irritating, scraping noise as they slide along the wire, or is it not easily heard over the rest of the noises?

Nope. A carbon strip is mounted on the top of each pan and this is what contacts the trolley wire. It's relatively soft so to minimize wear on the trolley wire and to facilitate crossover moves under wire.

BlackDog wrote:Got another question. I've been reading a lot of books on the Milwaukee and it's electrifird lines and I have some pantograph questions. On their Little Joes, the front pan is up on each unit. On their boxcabs, only one pan is up, and it's on the front. Why the front pan? And I am guessing that the boxcabs have a bus bar or something like that to distribute the juice drawn off the cantenary. Is that so? And do the pans make an irritating, scraping noise as they slide along the wire, or is it not easily heard over the rest of the noises?

I cannot comment on the Milwalkee Road pantograph use but I can tell you that it is usually common practice to use the rear pan when moving foward. The reason for this is that if you use the front pan and it gets snaged on the cat, it might rip off the roof and destroy the rear pan, and completly depower the loco. If you loose the rear pan than you still have the front pan to get you home.
Food for thought....
Jerry Kelley

Peter Radanovic wrote:Yes, the power-cars distribute their gained power throughout the rest of the train.

The Milwaukee Road units in question were freight locomotives, not MU cars. The power drawn from the pantographs was not distributed among the locomotives or between the locomotives and the train.

Also, are you stating that each power-car has two pantographs? If so, that might be to improve traction; if you're pulling something, you want to have the forward drive-set delivering more power, so as to increase the grip on the tracks. If you were to have the back deliver the most traction, you wouldn't have a good grip on the front end. However, I don't know if that's the case with your entity. That's just my speculation on this problem.

Although each locomotive had two pantographs, whether the front one or the back one (or both) was up had absolutely no effect on traction. The pantographs were electrically joined, so all traction motors received power regardless of which pan was being used. Although the decision to use the leading or trailing pantographs was primarily a matter of company policy, the reason jkrail gave above is the most common one I've heard.

A few Euro operations, mostly 1.5kv ones (NS, and I think old Britrail when they had it), use two pans on a loco as a means of splitting the load on each pan. They're electrically jumpered, though. Faviely now has a dual contact 1.5kv / 3kv pan that puts a copper strip to the wire at low speeds, to prevent localized heating. This isn't an issue on AC, because the voltages are high - low currents. An ALP-46 at full power draws maybe 400 amps on 25k?

The real pain is 600V DC overhead. It's very very constrained, which is why LRT voltages creeped up towards 750V over the years. AFAIK, nobody uses 600 volt overhead for mainline applications, though a few rapid transit type systems use it (notably Boston)

Also, MUs under 1.5kv or 3kv are easier than locomotives.

It's common for northeastern style married pairs to share a single pan. Years ago, the Reading shared pans between MUs via a roof bus.

The only US instance I know of multiple pans on the same electrical bus being used regularly is MN's New haven line - the M4/6 cars have 2 pans for three cars, and they are electrically tied together. That's why phase breaks are so long on that line.

Hi All,

One point worth mentioning. Although the engine usually ran with one pantograph up, in the dead of winter, with ice and snow, and icicles on the catenary, both pantographs were raised. The lead pantograph became an ice scraper and also ensured contact with the catenary.

This is still done, and in fact, the AEM-7 and ALP-44s (and I think 46, too) can have the pans electrically disconnected, so the leading one doesn't draw current (no arc!)

Makes sense - they're ASEA designs, and it snows in Sweeden.

MikeF wrote:The pantographs were electrically joined, so all traction motors received power regardless of which pan was being used.

I assume the non extended pantograph's conductive parts are still electrically charged?

Correct?
Good for firefigters/rescuers to know.

Thanks,

Robert Gift wrote:

MikeF wrote:The pantographs were electrically joined, so all traction motors received power regardless of which pan was being used.

I assume the non extended pantograph's conductive parts are still electrically charged?

Correct?
Good for firefigters/rescuers to know.

Thanks,

They are, and we do know, if the local electrically-powered rail property provides the training. SEPTA does do so in the Philadelphia area.

Hi,

Piece of trivia: When the GG-1's had to be refueled with fuel oil for their steam generators, BOTH pantographs were lowered and locked, and a ground wire was attached to the engine before refueling began. Standard Operating Procedure in the Long Island Sunnyside Yards.

Curious.
Why not generate steam with 100% efficient electricity.
Then you avoid installing heater, fuel tank, flue for combustion gasses, need to refuel tank, etc.

Is electricity not plentiful enough?

Thanks,

Why bother using electricity as a secondary fuel source when it makes just as good a primary? You're overcomplicating a simple idea.

If an electric "engine?" must produce steam for passenger car heating, why not do it with electricity, which you already have?

Too bad cars are not electrically heated, but I understand when they came from steam days, that was the system they had.

Electricity for heating is simple and 100% efficient.

Fuel oil requires tank, boiler, flue (which pulls air through boiler and cools everything when not burning) and other controls and piping, etc.
Plus refueling stations and storage tanks and the fueling storage tanks.

The Panographs on the AEM 7 can both be raised but both CANNOT be connected to the Main Transformer. Although the operator can open the MCB for Voltage Change / Phase Breaks, he cannot disconnect panographs. The Panograph selector switch that connects the panograph to the Main Transformer is Front, Back, or disconnected and has NO remote operator switch. If both Panographs were up & connected together when the unit transitioned a voltage Change / Phase Break it should MELT something during the explosion.

Also the Cantenary is "Zig-Zagged" so the pantograph shoe wears evenly. And as Pennsy stated the lead pantograph in an isolated state is utilized as an snow/ice plow.