Catenary/pantograph question

[tormadel]

Yeah I'm with you Micheal. It just seems that in the 1970's Milwaukee management was just hell bent on giving up. I've read a few different articles over the years saying the pacific extension (after the BN trackage rights) was the best hope for Milw.

It seems almost like someone with lung cancer decides to amputate a leg as a cure, just didn't make any sense.

That the PCE is gone yet the rinky dinky backassward line to Louisville survives (at least last I heard) just astounds me.

[MichaelSol]

QUOTE: Originally posted by tormadel
Milw would have been even better had the plan to connect the 2 parts of the electric operation would have come about. As I read the Milw went bankrupt in 1925 and that pretty much ended that.

The consulting engineers working for the Trustees, Coverdale & Colpitts, gave the electrification of the "gap" the highest priority, and it was in fact included in the capital improvement budgets for 1926 and 1927.

In September, 1971, Washington Water Power, Puget Power & Light and Montana Power Company proposed a plan whereby they would have, in effect, paid for electrifying the gap and provided new motive power.

In 1972 General Electric proposed electrifying the gap, and showed that doing so, with augmented power supplies and new motive power, provided an instant cash flow advantage over dieselization with SD-40-2s, an advantage that increased with the passage of time. GE did a cash flow analysis out to 2003, showing an accumulated net benefit to the Milwaukee of $402.7 million over the time period, assuming diesel costs increased at a 5% annual rate. That was before the explosion in diesel fuel costs that began in March, 1973. The study was prepared by the Locomotive Products Department, Transportation Systems Business Division, General Electric Co., dated March 20, 1972.

There had been comments on an earlier thread about costs of catenary. My recollection on DC catenary of the Milwaukee type was considerably different than some other opinions which went as high as $1 million per mile. I note that the GE study shows an estimate of $36,021 per mile for stringing catenary across the "gap" which was just about exactly my recollection based on our independent cost estimates. Another $2.9 million would have provided fully automated silicon rectifier substations across the "gap."

Although GE had its own locomotive --oops, "motor" -- proposal, EMD proposed to support the project with a modified SD-40-2 locomotive. Recognizing that the diesel version SD-40-2 was underpowered for its traction motor configuration, EMD offered a heavyweight, dual-use DC electric version of the SD-40-2 to the Milwaukee Road, rated at something like 6000 hp under the wire, continuous, with 25% adhesion. I suppose that would have been a real sight for railfans, #261 with Milwaukee pantographs on four SD-40-2s.

EMD also pitched a design based on ASEA proposals for Milwaukee, and ASEA discussed it independently with Milwaukee, for a 3,000 vDC "locomotive that would be very similar to modern Thyristor units in that each traction motor would be individually controlled and thus provide the advantages of the so-called modern AC "Chopper" locomotives" at 6,000 hp, 25% adhesion. [Letter, Upton to Kellow, 10/6/72].

It was a close call. The Electrification almost made it ....

[tormadel]

Ah ok, so the operations just were not extensive enough to make them worth while. The exceptions being the PRR northeast corridor and the Milw pacific operation. Milw would have been even better had the plan to connect the 2 parts of the electric operation would have come about. As I read the Milw went bankrupt in 1925 and that pretty much ended that.

[Kevin C. Smith]

Part of it was that the electric (tunnel/mountain) divisions weren't always very long (MR being the BIG exception). When most steam runs would be about 150 miles between engine changes, a 50 or 75 mile electric division (just using hypothetical numbers here) wasn't that different. Once diesels came in and could handle a run for 500-600 miles, it wouldn't make sense to trade power for a relatively small part of that run. It would just add one or two locomotive changes (with attendant terminals, yards & shops, possibly).

[tormadel]

My comment is just that Electrafied routes always seemed to me like a good idea. Disels are more exciting [8D] but electric units do have good points. I know one of the big arguements against it is that it's very expensive to install. But, there are some parts of the country that used to have them and don't anymore. I know is some cases disels overcame the tunnel issues but it still seems like keeping the electrics would have been a good idea. Why was this not so?

[daveklepper]

You are on the ball. The New Haven electrication preceded the PRR's AC electrification and set the standards for it, the Reading's suburban electrication, and the second GN electrification -and Hoosack Tunnel on the B&M.

[CSX FAN]

Dave

THanks for the tip. I found one old artical that detailed the cross over pieces an extention of New Haven. It was written in 1912 Sorry I forgot the railroad. It detailed how a deverging line would be OK for the pantogragh but the second line would tend to droop and then would fall under the pan and snag it. Causing great damage to the pan and the Catenary. By building the box both pieces of cat are raised as the pan goes by keeping them even, thus the pan would not get snagged. The distance is from 5' to 2' in the artical. the area below 2' would automaticaly raise it self. The converging direction doesn't mater.

Jamie

[daveklepper]

Yes. Call up the website for the Light Railway Transit Association (actually headquarted in London, England): www.lrta.org

Then go to links, then to clubs and historical groups

Then find the website of the Electric Railroaders Association

They should be able to help you. Or you can search with Google

One of the historical societies for the Pennsylvania Railroad would have the details on the catenary. also, I would think.

The book "Route of the Electroliners" of the Central Electric Railfans Association, also with a website, and accessable through the LRTA's, does have a scale drawing of the cantenary towers of the Skokie Valley line of the CNS&M (North Shore).

One of the ERA railfans should have access to the material you want.

Gibbs and Hill were the engineers. Their offices were in one of the two World Trade Center Towers. They are not currently in business, even via a successor firm. So I doubt we can put our hands on the original drawings. There should be plenty of copies though.

Another source might be Amtrak's Northeast Corridor operation, and their offices are at the 30th Street Station in Philadelphia, but you might have to go through the the Washington DC offices at Union Station first. They definitely have copies of the drawings.

[CSX FAN]

Would any of you know where I could find blueprints of the PRR catenary system? I'm modeling the PRR cat and was having problems in my Yards and with cross over air gaps. I think I resolved the cross over issues out on the line yesterday, but haven't addressed the yards yet.

Thanks

Jamie

[daveklepper]

Note that for many years streetcars did use trolley wheels, but around WWII, when hard graphit became available, shoes started replacing wheels, and even some of the heritage operations that try to be authentic uses shoes, including most trolley museums,

[Anonymous]

Thank you all for your information!

Erik

[CSSHEGEWISCH]

The bearings on roller contacts also had the bad habit of throwing out their lubricant all over the place, leading to the problem mentioned above.

One further word on South Shore, while the MU cars raised the rear pantograph, freight motors (R2's and Joes) raised the front pantograph, the reason for the difference in operation is unknown.

[Anonymous]

In the very early days there was some experiments using roller contacts on top of pantographs. It was fairly quickly found that there was less wear on the steel wire when copper and later carbon wear pads were used instead. Not even considering what would happen to the wire structure when one of the bearings on the roller would eventually fail.

[MichaelSol]

QUOTE: Originally posted by erikthered

All the information here is great- thanks everyone! Electric locomotives seem to have "shoes" (for lack of a better word) on top of their pantographs while trolley cars have, well, trolleys- flanged wheels at the top of the pole.

A couple of questions- First, would not the pantograph "shoes" cause some kind of wear on overhead wiring, particularly with a train at high speed? I know that some interurbans were capable of fairly high speed, and they seemed to have poles with trolleys. Did the railroads experiment with a roller type arrangement on the pantograph? Wouldn't that reduce wear on the wiring? Seems to me that a shoe in contact with wire moving at 80 plus MPH would cause a lot of friction and heat....

The Butte, Anaconda & Pacific first tried rollers on the pantographs. By the time the Milwaukee Road's higher voltage operation was finished, GE had changed the pantograph design to copper shoes mounted on the pantograph bar. The copper shoes were replaced periodically. There was some contact wire wear. A graphite grease was soon added to the copper shoes, and this ultimately was worked into the contact wire surface, created a mirror smooth finish. The overall wear after that point was neglible. When the wires came down in 1974 on the RM, they were the same wires that had been installed in 1915. Their estimated life span at that point was judged to be indeterminate because of the lack of wear since the introduction of the graphite grease.

The overall catenary/pantorgraph design was estimated to handle maximum speeds of 150 mph without overheating or adverse effects from harmonic resonance.

Best regards, Michael Sol

[BR60103]

I heard that the idea of using the rear pantograph was that if it snagged and tore loose, it would not carry off the other pan. Makes less sense when there are 7 (or 14) other pans behind it.
The pantographs usually have carbon shoes on the main contact section. Streetcars (lately, anyway) have a cabon insert in the trolley shoe. This was intended to wear more quickly than the contact wire.

[Anonymous]

All the information here is great- thanks everyone! Electric locomotives seem to have "shoes" (for lack of a better word) on top of their pantographs while trolley cars have, well, trolleys- flanged wheels at the top of the pole.

A couple of questions- First, would not the pantograph "shoes" cause some kind of wear on overhead wiring, particularly with a train at high speed? I know that some interurbans were capable of fairly high speed, and they seemed to have poles with trolleys. Did the railroads experiment with a roller type arrangement on the pantograph? Wouldn't that reduce wear on the wiring? Seems to me that a shoe in contact with wire moving at 80 plus MPH would cause a lot of friction and heat....

Thanks,
Erik

[Murphy Siding]

BrianLM007: Thanks for the links. I understand what you're saying now. Any explanation about why the trailing pantograph would normally be used-what difference would it make? Thanks

[BrianLM007]

Looks like CSSHEGEWISCH and daveklepper answered pretty well for me, but I will also add this: there are 68 cars in the fleet. The breakdown is as follows:

Cars 1-48: MUs, 2 Pantographs at each end, 2 cabs (one at each end).

Cars 101-110, MUs, 2 Pantographs at each end, 1 cab (If the car is on a North-South track, cars 102, 104, 106, 108 and 110 have a cab at the North end, and cars 101, 103, 105, 107, 109 have their cabs at the South end).

Cars 201-210, Trailers, 1 Pantograph (If the car is on a North-South track, the pantograph is on the South end of the car).

A typical 8 car consist often looks like this:

MU - MU - Trailer - MU - MU - Trailer - MU - MU

You normally see 8 pantographs raised while in operation. When it is very cold, however, you will often see both pantographs raised on the first car (so there are 9 pantographs up during those times).

To give you an idea of what you are looking at, here are a couple of links of South Shore Cars:

NICTD Car #1 (From the Nippon-Sharyo (manufacturer's) website):

http://www.n-sharyo.co.jp/business/tetsudo/pages/zchicago.htm

A WB train from South Bend (From Thomas Kepshire's website):

http://www.monon.monon.org/railpixs4/07-18westbound2.jpg

Hope that helps.

BrianLM007

[CSSHEGEWISCH]

South Shore's MU cars, both from the Insull era and the present versions, have always had two pantographs. South Shore's operating rules state that the trailing pantograph is to be raised unless circumstances demand otherwise.
The Insull era trailers (12 coaches, 2 eight-wheel parlors later converted to coaches, 2 twelve-wheel parlors and 2 twelve-wheel diners) never had pantographs, but the coaches did have control cabs. The current trailers do have pantographs for heat and light but do not have control cabs or end windows.

[Kevin C. Smith]

QUOTE: Originally posted by Dutchrailnut

clearances to ground for 1500 volt is about 4"
for 11.5Kv is about one foot
for 25Kv is two foot

These clearances are to be doubled since you need clearance between structure and wire, plus between wire and train.

Wow-WAY less than I'd have thought. How come the clearances in practice are so much more? It seems to me a GG1 pantograph would rise to about 3-4 feet to make contact. Or am I (again) grossly mis-estimating?

[daveklepper]

Most mu's and electric locos have two pantographs, assuming they are bidirectional and almost all are. Generally each pan. is located over a truck center to insure alignment with the overhead wire. The rear pantograph is the one normally used. The theory is that if there is trouble, the front pantograph in store position has alreay passed the bad spot and can be used to continue operation.

Other than special trains hauled by locomtives, the South Shore has always used self-propelled electric cars, single cars for the very first few years and then and now mu cars. There are a few non-powered trailers without pantographs.

[Murphy Siding]

QUOTE: Originally posted by BrianLM007

You also get a "twang" sound when the pantograph makes contact with the catenary, particularly if there are multiple pantographs. You see this on the NICTD platforms at the Randolph St. Station when the South Shore engineers will switch the pantograph positions (he/she will first lower all the pantographs, of which there can be up to 8, than after about thirty seconds, he/she will raise the opposite pantographs) in preparation for departure back to Indiana.

You can get quite a little show while you wait to board!

BrianLM007
A South Shore Regular

I'm really unfamiliar with this. Does the South Shore have MU cars, so that each one has an individual pantograph? Is there a pantograph at each end of the car,for example, one for going north, one for going south?? Can you expand on that please? Thanks

[BrianLM007]

You also get a "twang" sound when the pantograph makes contact with the catenary, particularly if there are multiple pantographs. You see this on the NICTD platforms at the Randolph St. Station when the South Shore engineers will switch the pantograph positions (he/she will first lower all the pantographs, of which there can be up to 8, than after about thirty seconds, he/she will raise the opposite pantographs) in preparation for departure back to Indiana.

You can get quite a little show while you wait to board!

BrianLM007
A South Shore Regular

[daveklepper]

Sometimes a flash is acompanied by a sputtering kind of sound, and this can happen both with third rail and with trolley wire.

[Kevin C. Smith]

QUOTE: Originally posted by daveklepper

.

I was not aware of any reduction in the 11,000V 25Hz AC PRR tunnels either in NY or in Baltimore (equally restrictive). Perhaps that is becauses improved insulation materials made the voltage reduction unnecessary at a certain time.

OR-and this is far more likely-I am entirely mistaken.

[BR60103]

Murphy: the sound is a sharp "pop". It's the sound you get when you unplug a kettle, but bigger,
The Toronto subway produces flashes when the shoes beak contact with the 3rd rail at switches, a nice big blue flash. There was an article in a British mag about sumulkating the flash -- I think they used a photo flash unit.

[Murphy Siding]

QUOTE: Originally posted by trainboyH16-44

QUOTE: Originally posted by Murphy Siding

Some have mentioned sparks, flashes, and such. Were/are those type things common with overhead catenary? Things like that would scare the bejeebers out of me.

It's not as scary as you might think, and it's incredibly common, even with new LRTs. When I take it to school in the morning, there's this weird section in a tunnel where blue flashes light it up, and it's pretty neat to watch!

I realize these are *dumb* questions, but i am perhaps 1,000 miles away from an electric train line........Are the flashes accompanied by sound? I'm imagineing a big *BZZZZ* like a bug zapper(?) Truely, I have no idea what it is like). Thanks

[ndbprr]

Trolly contact is different than high speed trains. Generally a trolley either uses a wheel or a contact shoe with a frog for lack of a better description. The car movement and pole tend to pull the shoe or wheel in the correct direction. On high speed corridor trains the contact wire has a second wire clipped to the first in the same manner the contact wire is supported. If you look closely at a high level platform you will see that a clip grips the upper half of the wire and has a nut and bolt to squeeze and hold the contact wire. It is a fairly simple procedure to just have a short length of catenary to connect tracks through turnouts. Arcing also occurs in wet weather when the shoe hydroplanes from the water hanging on the wire.

[daveklepper]

There are special trolley wire frogs that join or have cross to trolley wires while keeping them both on the same level, with grooves for the sides of a trolleywheel or trolleyshoe as used on trolleypole streetcars and itnerurban cars and locomotives, including the North Shore when it was running. Panatographs have no trouble with these when properlly designed, but a more usual practice is simply to parallel the two wires for a few feet, while the pantograph is contacting both wires. Special insulated trolley frogs are used for crossings of trolleybus and rail lines or two trolleybus lines where the frog in the air is an insulated "dead" zone.

I was not aware of any reduction in the 11,000V 25Hz AC PRR tunnels either in NY or in Baltimore (equally restrictive). Perhaps that is becauses improved insulation materials made the voltage reduction unnecessary at a certain time.