Catenary/pantograph question

[BR60103]

Can anyone confirm that at switches one contact wire would run above the other? Not sure how that affected the Pantograph contact. I'm sure at high-speed turnouts they tried to run the wires parallel for a section.
The Edmonton trolley line had an interesting bit of overhead. The line came to the surface and crossed a trolley bus line at grade. Fortunately the crossing was an acute angle. There was a little bit where the trolley line was bent to parallel the trolley bus wire and a stretched Z shaped piece in between so that the pan didn't lose power. I suspect the trolley bus wire was a bit higher than the trolley so that they didn't short to the return wire.

[jchnhtfd]

The arcing is almost inevitable at any kind of speed at all, as the pantograph is held against the wire by springs, and both the pan and the wire can move -- and lose contact now and then. Sometimes on very high speed service (and also, due to the peculiarities of the machinery, on some of the old Milwaukee motors) both pantographs are used at once, to minimize the problem.

[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!

[kenneo]

QUOTE: Originally posted by beaulieu

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.

Happens fairly often at speed. Kind of neat to watch at night.

Steam = smoke signals

Electric = Arc signals (aka "hot flashes" when unit is over age 50)

[beaulieu]

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.

Happens fairly often at speed. Kind of neat to watch at night.

[David_Telesha]

Its arcing. Happens when the pan bounces or temporarily looses/re-makes contact.

[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.

[Isambard]

QUOTE: Originally posted by jchnhtfd

One might also mention -- in connection with gaps -- that a number of the NYC motors which worked Grand Central had tiny (and I do mean tiny -- so small they looked really silly!) pantographs on each end, and at some really complicated switchwork there were short sections of catenary in place of the third rail, to keep things moving. Otherwise, you just coast through the dead section.

Of course, if you stop... the dispatcher tends to get a bit fractious.

Aha, the mystery that has bothered me since was a kid is now explained. I had inherited my uncle's mid 1930's Lionel train, which was headed by an NYC electric loco in orange, with a cab in the centre, and those tiny pantographs, which indeed looked silly to me, since I was a fan of the Great Northern and Milwaukee Road electrics with their impressive pantographs.

[:)]

.

[Isambard]

QUOTE: Originally posted by jchnhtfd

One might also mention -- in connection with gaps -- that a number of the NYC motors which worked Grand Central had tiny (and I do mean tiny -- so small they looked really silly!) pantographs on each end, and at some really complicated switchwork there were short sections of catenary in place of the third rail, to keep things moving. Otherwise, you just coast through the dead section.

Of course, if you stop... the dispatcher tends to get a bit fractious.

Aha, the mystery that has bothered me since was a kid is now explained. I had inherited my uncle's mid 1930's Lionel train, which was headed by an NYC electric loco in orange, with a cab in the centre, and those tiny pantographs, which indeed looked silly to me, since I was a fan of the Great Northern and Milwaukee Road electrics with their impressive pantographs.

[:)]

.

[wallyworld]

I used to live next to the Chicago North Shore and Milwaukee station in Mundelein. This was a electric interurban with both catenary and direct hung contact wire at 600 volts DC. They would install "sleet cutters" on some Merchandise Dispatch cars and run them to clear ice from the overhead. The road also ran on 3rd rail and sleet cutters were used on the 3rd rail as well. Some interurban cars had a control to the right of the brake on the control stand to put a 3rd rail sleet cutter into action. The arcing could be pretty spectacular on the overhead especially at cross-overs where the pole had to be pulled down and set back on the wire while the cars where in motion by a conductor hanging out the rear door pulling on the retriever rope. I was always amazed they did this at night as well or in other bad weather like blizzards, heavy rain etc and managed to hit the wire every time I watched them. And then...flash! It was interesting to watch.

[dldance]

Many of the pictures posted at the following web site show Swiss electrical overhead from the engineers view. The camera is in the cab of a Swiss engine and posts a picture to the internet about once every 15 minutes.

dd

http://home.rol3.com/myswitzerland/Livebild.jpg

[CSSHEGEWISCH]

The Chicago, Aurora & Elgin, which was primarily a third-rail operation, had a stretch of trolley wire strung over an especially long grade crossing which included a regular station stop near the roadway. Coasting across the grade crossing could be difficult when attempting to accelerate away from the station so the wire was in place to prevent stalls in the dead zone.

NYC installed overhead third rail, not catenary, in GCT and in parts of its Detroit River electrification to cover the gaps, especially around double slip switches.

[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.

[Anonymous]

I believe the Southern Railway (this side of the Atlantic) built a series of three 3rd-rail electric locos with large flywheels (numbered CC1-CC3, later Class 70) fitted in order to deal with breaks in the conductor rail. There was also some overhead wiring fitted in yards to avoid the risk to crews of 3rd rail - tram-type overhead was used to keep costs down as at yard speeds it functioned perfectly well, and the later Class 71 was also fitted to work from this overhead along with 3rd rail.

Link to Class 70 page : http://en.wikipedia.org/wiki/British_Rail_Class_70

Link to Class 71 page: http://en.wikipedia.org/wiki/British_Rail_Class_71

[Kevin C. Smith]

QUOTE: Originally posted by daveklepper

Note that there were a variety of voltages and power used in electrification. Today, a Washington to Boston train starts out using the original 11,000 volt 25-cycle ac electrification, switches to 60-cycle, 25,000 volts just beyond Harold Tower, Sunnyside, on the Hell Gate Bridge approach, then to 12,500 volts to enter Metro North tracks at New Rochelle, keeping 60 cycles per second ("Hz"), then back to 25,000 volts when east of New Haven station and keeps that on the new electrification up to Boston.

And a Metro North commuter train uses 60Hz power from New Haven to Mount Vernon, then coasts while dropping pantographs and having its third rail shoes pick up 650volts dc on the third rail into Gramd Central Terminal.

And Metra Electric and the South Shore both use 1500 volt DC on overhead catenary.

Most new light rail systems use 750 volts DC on catenary and older systems, including new extensions, 600 volts DC on simple trolley wire.

The Milwaukee used 3000 volts DC in its catenary except when on tracks shared with the Butt Anaconda and Pacific where the voltage dropped to 2200 volts.

And the new standard in Europe is 50 Hz AC because that is the standard power frequency there, but there are plenty of 16-2/3 Hz electrications and plenty of 1500 volt DC, 750 volt DC, 3000 volt DC and 600 and 550 volt DC electrifications around.

I know the PRR reduced the voltage in the Hudson River tunnels when they strung overhead wires, due to limited clearance. Which got me wondering-what are the minimum clearances (above equipment) for the most common electrification voltages-1,500/11,000/25,000 volts? Does AC or DC make any difference? I've heard many times that a major cost of electrification is raising overhead structures, so I know you just can't staple a 25kv line to the underside of a bridge. (You think the thread about trains stopping on a bridge with no walkways was funny until the typo got fixed; I just did it here, too!-but caught it in time. Still, it read hilarious!)

[David_Telesha]

no, you're dealing with an electric motor and a train thats a few dozen tons at least.

[Murphy Siding]

QUOTE: Originally posted by CSSHEGEWISCH

As far as coasting through a dead zone, it isn't that much of a problem if the train, locomotive or MU car has enough momentum

I was kind of thinking of how your car would react, if you turned the motor off for 5,10 or 30 seconds, then it started back up. Wouldn't this cause some "rough riding"?

[rrandb]

QUOTE: Originally posted by jchnhtfd

One might also mention -- in connection with gaps -- that a number of the NYC motors which worked Grand Central had tiny (and I do mean tiny -- so small they looked really silly!) pantographs on each end, and at some really complicated switchwork there were short sections of catenary in place of the third rail, to keep things moving. Otherwise, you just coast through the dead section.

Of course, if you stop... the dispatcher tends to get a bit fractious.

This was also used where a third rail system had a grade crossing. A third rail can not cross a road and the gaps are too long to trust to coasting. There were short sections of cantenary across the hyways. As always ENJOY[2c]

[jchnhtfd]

One might also mention -- in connection with gaps -- that a number of the NYC motors which worked Grand Central had tiny (and I do mean tiny -- so small they looked really silly!) pantographs on each end, and at some really complicated switchwork there were short sections of catenary in place of the third rail, to keep things moving. Otherwise, you just coast through the dead section.

Of course, if you stop... the dispatcher tends to get a bit fractious.

[BaltACD]

Aunt mildred's new dog in contact with the catenary - TOASTY!

[dldance]

A news report on KSL-TV 15 mar 2006 talked about the winter weather design features that were included in Salt Lake City's TRAX light rail. Thanks to a combination of automatic switch point heaters and running extra cars throught the night to keep the wire and rail clear, TRAX was running on time -- even though areas of SLC got up to 2 feet of snow. Auto traffic was backed up for several hours on the other hand. That means that some TRAX riders beat their bosses (the ones with the office keys) to work. That demonstrates some of the bad weather capability of light-rail.

dd

[ndbprr]

the only location I know of where PRR Motors ( not electrics in PRR lingo) were worked on in a roundhouse was Enola yard west of Harrisburg, PA. They did not enter under their own power but were placed by a switcher. All the PRR motors had car bodys that were removed from the frame like a diesel today. Catenary would have prevented that. A multi story building with an overhead crane is the main requirement for working on them. Basically the guts just had a way to step down the voltage to the traction motors, blowers to keep things cool, air compressor, and a flash bolier to heat cars. That is why they last so long.

[CSSHEGEWISCH]

Catenary over yards, junctions, station throats, etc. takes on the appearance of a giant copper cobweb pretty quickly. You need contact wire over all tracks to keep everything moving.

As far as coasting through a dead zone, it isn't that much of a problem if the train, locomotive or MU car has enough momentum. Third rail electrifications have a problem with gaps in yards, though. NYC's S-motors were short enough that they had a problem with the gaps in open yards where an overhead third rail was not available. NYC worked around that problem by assigning T-motors, which were longer, as switchers at Harmon.

[oltmannd]

QUOTE: Originally posted by jchnhtfd

A few comments... on current. It's watts that do the work -- voltage times current. On the 11,000 volt electrification on the NEC, the maximum draw is on the order of 500 amps per motor (locomotive/engine whatever). That will give you about 8,000 hp -- which is what those things put out at max. 500 amps isn't absurdly high, no... but it's right up there. One of the major advantages of using AC electrification is that it is very easy to transform the high voltage down to something a little less zippy inside the cab. The other, however, is that the arc which forms when the pan skips on the catenary tends to extinguish itself, as the current drops nearly to zero twice per cycle.

In older catenary designs the heating from the current draw could, and did, cause the catenary to droop, with unfortunate results.

Ice storms cause absolute havoc -- not because they insulate the wire (although that was a problem with streetcars, with relatively low contact pressures) but because they either cause the cat to droop too much (and it can get arount the end of the pan, catch, and be pulled down) or just simply break. I've seen both happen.

The catenary and suspension wires are never insulated. The insulators are the hangars to the poles or cross suspenders. You definetly do not want to touch -- or come anywhere near -- energized catenary.

PRR/PC/CR had rules on operating E44s when 3 were MUed to avoid catenary meltdown.

[Murphy Siding]

Are there any considerations where where tracks wye or cross, such as a "break" in the supply line? Or, is it just a matter of there being a cat wire above every piece of track, including into the roundhouse? Mention is made of situations where the "juice" comes disconnected for, perhaps short periods of time. How does that affect the motion of the train? Lots of questions, I know, but one doesn't think much about electric train operation in S.D. Thanks

[tatans]

Just a comment, These above answers are the best responses to a simple question I have read in this forum, everyone seemed to understand the question and responded with a straight, concise answer,and did not veer off the subject about Aunt mildred's new dog. hope to see a lot more responses like the above, thank you. ( I wasn't that interested about caternary until I read all the responses)

[daveklepper]

Note that there were a variety of voltages and power used in electrification. Today, a Washington to Boston train starts out using the original 11,000 volt 25-cycle ac electrification, switches to 60-cycle, 25,000 volts just beyond Harold Tower, Sunnyside, on the Hell Gate Bridge approach, then to 12,500 volts to enter Metro North tracks at New Rochelle, keeping 60 cycles per second ("Hz"), then back to 25,000 volts when east of New Haven station and keeps that on the new electrification up to Boston. A restored GG-1 could run only from Synnyside yard to Washington but not up to Nerw Haven or Boston.

And a Metro North commuter train uses 60Hz power from New Haven to Mount Vernon, then coasts while dropping pantographs and having its third rail shoes pick up 650volts dc on the third rail into Gramd Central Terminal.

And Metra Electric and the South Shore both use 1500 volt DC on overhead catenary.

Most new light rail systems use 750 volts DC on catenary and older systems, including new extensions, 600 volts DC on simple trolley wire.

The Milwaukee used 3000 volts DC in its catenary except when on tracks shared with the Butt Anaconda and Pacific where the voltage dropped to 2200 volts.

And Cincinnati and Havana streetcars used two trolley poles like trolley buses because ground return via rails was prohibited because of possible interference with telephone cables in the street.

And the new standard in Europe is 50 Hz AC because that is the standard power frequency there, but there are plenty of 16-2/3 Hz electrications and plenty of 1500 volt DC, 750 volt DC, 3000 volt DC and 600 and 550 volt DC electrifications around.

Those of us who rode streetcars in the old days remember winter storms when the lights would blink out and a lightning display but light up the street as arcs formed between the trolley wheel or shoe and the wire. The most dramatic ride I ever had in such a situation was on the Evergreen line in Pittsburgh, the remnant of the old interurban north to New Castle with connections to Buffalo, and this was the last of the non-PCC old Peter-Witt equipped lines to enter downtown Pittsburgh, all the other lines used modern PCC cars. The old cars were kept on that line because of the lack of a loop at the north end, and all PCC's in Pittsburgh were single-end cars. The schedule went out the window because of the fitfull progress going north and back to the city.

[David_Telesha]

QUOTE: Originally posted by ndbprr

If you are not from the east coast you have no idea how sloppy the snow and ice are in PRR electrifed territory. Slush is a better description. A standing order was that all trains have both pantographs up during sloppy weather to help keep the catenary free of ice build up. Don;t forget that the PRR ran trains four tracks wide with about ten minutes between trains on all four tracks so build up would be minimal. It was also the job of the fireman to get out at every stop and check the pantograph shoes for arc through. The back pantograph was used in dry weather in case it got fouled and ripped off which did happen in which case the front one could the fini***he trip. Originally the PRR used carbon shoes on the pantographs but in the early 50's switched to steel shoes because of wear and cost. The catenary is not centered over the track but zig zags to even out the wear on the shoe and prevent grooving. The GN engines the PRR purchased were the only engine that required both pantographs be used in operation. This is because they were motor generators in which the AC from the catenary turned a motor that turned a generator to produce DC for the traction motors. In order that the motor not get out of phase with the power the pantograph had to be in contact with the wire 100% of the time. Sometimes they do bounce off the wire so two were the order of the day alsways.

For many points, all I have to do is change PRR to NHRR and you did all the work for me! Thanks!

BTW, for the many drawbridges the NH had between NH and NY there were gaps in the wire. The train had to glide through the gap - the wire went really high at either side of the gap so the pantograph eased to max height and then made smooth contact again at the other side.

Bouncing pans caused arcing, and if they bounced too hard would vaporize - no joke.

[CSSHEGEWISCH]

As far as the dangers of energized catenary and induction currents, the Special Instructions in PC employee timetables for those lines stated that there was a danger zone of 24 inches from any energized catenary. Anybody who has been to the Northeast is also aware of the shields on overhead bridges over electrified tracks, including on I-95, which doesn't have sidewalks.

[jchnhtfd]

A few comments... on current. It's watts that do the work -- voltage times current. On the 11,000 volt electrification on the NEC, the maximum draw is on the order of 500 amps per motor (locomotive/engine whatever). That will give you about 8,000 hp -- which is what those things put out at max. 500 amps isn't absurdly high, no... but it's right up there. One of the major advantages of using AC electrification is that it is very easy to transform the high voltage down to something a little less zippy inside the cab. The other, however, is that the arc which forms when the pan skips on the catenary tends to extinguish itself, as the current drops nearly to zero twice per cycle.

In older catenary designs the heating from the current draw could, and did, cause the catenary to droop, with unfortunate results.

Ice storms cause absolute havoc -- not because they insulate the wire (although that was a problem with streetcars, with relatively low contact pressures) but because they either cause the cat to droop too much (and it can get arount the end of the pan, catch, and be pulled down) or just simply break. I've seen both happen.

The catenary and suspension wires are never insulated. The insulators are the hangars to the poles or cross suspenders. You definetly do not want to touch -- or come anywhere near -- energized catenary.