Correct, and the conventional tie (sleeper to the British) T-rail track on the Benning, Cabin John, and Branchville lines were all under overhead wire with the plow pits at the changeover points.
At one time DC did have some streetcars for conduit operation only without trolley poles, and these were center-door two-man cars used on 14th Street (50, 51, 52). But during WWII and afer, all DC cars were equipped for both wire and conduit, and this seemed to be trued even at the end when all the wire portions of the lines had already been converted to bus. Posssibly wire operaton was still needed in the car houses.
DC Transit ran streetcars on a grassy median on Pennsylvania Ave. SE and had to pave the area of the tracks and between the tracks.
Bernie Fliger
Thanks for the info, Paul. Washington DC is indeed really interested in re-implementing the streetcar system. It's already being built in Anacostia and Benning Road areas. Recent media reports that they do intend to re-implement significant parts of the original system. I believe they are to use a new ground-conduit system that is not buried, but is on the surface, and it only energizes portions of the ground conduit directly below the train cars.
In certain areas it will be "hybrid" and will use on-board batteries, but I'm fairly sure that won't be the only solution to make the streetcars work within the DC core areas where they expressly forbid overhead wiring.
In Washington DC and, I believe, parts of the New York City streetcar system, there was special engineering to handle the below-ground power supply. At regular intervals are "vaults" which workers must regularly open to clean out debris. The idea was that dirt and detritus that collects in the ground conduit slots would be pushed by the ploughs and make its way into these vaults. Then, workers clean out the vaults.
The system was so resilient that most streets in NYC and certainly DC that had these ground conduits still have the conduits and their garbage vaults existing today under the pavement. This is mostly due to the fact that they're built of extremely durable concrete, iron, and steel structures that are cost-prohibitive to remove.
I know of zero systems that were successful that used only the running rails and conductors, because of the problems with insulation in the wheels. The stud contact and sectionalized contact systems you are referring to all used rails or studes in the center, between the running rails.
Was the proposal for a system that used the running rails as the contact rails? I saw an article about a system in France were the rails that the streetcars ran on were electrified. The system used a series of short sections that would only be electrified when the streetcar was directly above the section of track that was electrified. When the streetcar moved off the section the power was automaticly turned off.
I'll try to see if I can find the article.
Thx IGN
WALT1ORO As with many underground systems where electric is exposed to the weather and wet conditions they did not function well without much repair, maintenance and most were removed after a very short time. The system in Washington DC lasted until 1950 when the streetcars were removed and replaced by bus transportation.
As with many underground systems where electric is exposed to the weather and wet conditions they did not function well without much repair, maintenance and most were removed after a very short time. The system in Washington DC lasted until 1950 when the streetcars were removed and replaced by bus transportation.
The Washington DC streetcar system was abandoned over a period of years, but the bulk of it remained in service until January 1962. Congress (in its infinite wisdom) had decided that streetcars made the city look old-fashioned and had mandated that the streetcars be removed by June 1962. DC Transit, the system's operator, decided to pull the plug six months early. Special runs were made all day on the last day, including with some historic equipment.
Bombardier's PriMove induction system is the one that was specifically mentioned in the cited Railway Age article as being suitable for grass-covered areas.
The sidebar in that article on the Washington, D.C. research and current construction of 2 streetcar lines - " 'Wireless Zone' Drives D.C. Shopping" on pg. 32 (a poor title, I think) - can be found here:
http://www.nxtbook.com/nxtbooks/sb/ra0811/#/34 and/ or http://findarticles.com/p/articles/mi_m1215/is_8_212/ai_n58104767/
- Paul North.
I have no doubt that either a battery system or a capacitor or inductor induction system would work OK in grassy areas, but regardless of manufacturers' claims, I have doubts about contact systems.
This should be a direct link to an on-line version in "Nxtbook" format of the Railway Age article: http://www.nxtbook.com/nxtbooks/sb/ra0811/#/30
If that doesn't work, here's a link to a text-only version of it (no photos, so considerably less helpful): http://findarticles.com/p/articles/mi_m1215/is_8_212/ai_n58104766/
Another lengthy article from Mass Transit magazine, dated June 2011, by John Phythyon: "The Future is Here: Catenary-less Power for Light Rail", at: http://www.masstransitmag.com/article/10262406/the-future-is-here-catenary-less-power-for-light-rail
Ansaldo STS's TramWave - see: http://www.ansaldo-sts.com/en/media/press_releases/asts_2009_06_09_tramwave_eng.html and
http://www.sirio.tw/images/documents/TramWave%20eng.E.pdf (28 pages/ slides, approx. 1.65 MB in size).
Alstom's APS 3-D Animation (About 3 mins. long): http://www.alstom.com/transport/news-and-events/events/alstom-in-Innotrans-2010/sustainable-mobility/APS-3D-animation/
The other on-board power supplies mentioned in the Railway Age article were Kinkisharyo's "ameriTRAM" with a lithium-ion battery which demonstrated here in the US last year; Kawasaki Rail Car, Inc.'s Smooth WIn MOver (SWIMO) streetcar with nickel metal hydride battery; Siemens Sitras Hybrid Energy System (HES), also with an NMH battery plus a double-layer capacitor; CAF's Spanish ACR with an onboard supercapacitor; and Oregon's United Streetcar LLC "United 300" (power not stated).
A "sidebar" article on Washington, D.C. summarized consideration of many of these systems for its planned streetcar system, especially the core central "Federal District" and historic areas where overhead wires would be banned.
Relative to daveklepper's Original Post, some of the articles and public information releases for these systems specifically menion that they can work in grassy areas, too.
I'll see if I can find a link to that Railway Age article. In the meantime, suggest "Googling" any of them for more info.
The article was in the August 2011 edition of Railway Age - "Suppliers Eye Market for 'Hybrid' Streetcars", by Douglas John Bowen, Managing Editor, pp. 29 - 33 inclusive.
Ansaldo STS's "TramWave", Bombardier's "PriMove", and Alstom's "Aesthetic Power Supply" were featured, along with 3 or 4 other battery or fuel-cell systems. More later.
There are some systems that use one of these techniques that have operated successfully for more than one year in France. Marceilles is one city. I think the power on-off for when the car is overhead is done via radio control. The stuff does require maintenace and is about four times as expensive as overhead wire for an equal distance.
Paris had a similar system in the early 1900's with spring loaded button studs which made electrical contact when depressed by the shoe under the street cars. As with all such systems after a short time accumulations of dirt, ice or weak springs left some of the studs still down and 'Live' which resulted in a few horses being shocked and running away or being killed if water was also present on the streets.
There may yet be a fail-safe system where the cars can be detected and power can turn on exactly under the car and off as it passes or a linerar magnetic field in cables under the right of way may transmit power to the car without exposed overhead or third rail supplies.
A few months ago Railway Track & Structures magazine (or similar - I'll see if I can find it and provide a full citation) had a 'sidebar' article on these trolley or tram systems without overhead or 3rd rail power supplies. Another one that was depicted in it was a 'stud' system that would be sequentially activated as they were contacted by 'skates' under the cars. For about the last 10 years a segmented middle 3rd rail system (Joshua Lionel Cowen is redeemed at last !) has been functioning in much the same manner - see: http://en.wikipedia.org/wiki/Ground-level_power_supply and http://en.wikipedia.org/wiki/Stud_contact_system
I have seen some pictures of ground contact systems in what looks like grassed track. On checking, turns out it is artificial grass. something like Astroturf.
Since most of the early cable car and later electric streetcar lines which had the underground vaults for their cables or electric contact were in operation thousand of horse drawn vehicles were in daily use above ground. The track crews had another dirty job of cleaning the vault which was a constant problem with the horse waste and soils washed into the vaults by rains. In addition, since many homes and business burned coal for heat or production the ashes and cinders were spread on the unpaved streets and snow to help improve travel since cinders are hard and could firm up the muddy roads. All of which washed into the underground vaults for the track crews to remove in order to keep the systems running.
Salt on the streets came later in the 1920's as coal burning became less popular in the cities and with paved brick or concrete streets, with new maintenance costs for the street railway systems.
The vaults in most cases were simply paved over after abandonment of the streetcar systems and some sections of the old systems may still be seen in London and in D.C. where the pavement has not yet covered the past or by careful observation of a small depression in the middle of streets where asphalt is pressed down into the vault trough by the weight of traffic.
I can confirm that these problems occasionally happened in Manhattan.
As a D.C. resident in the late 1950s and early 1960s I can tell you that salt did cause problems with the Capital Transit streetcar plows, in that the salt and plenty of melting snow made a wonderful electrolyte for shorting out the below-ground busbars of their conduit system. Another problem was that cars with tire chains mounted on the wheels would sometimes get the chain torn off by getting it caught in the conduit slot, and if there was enough loose chain to contact a busbar below then more fun would ensue (or similarly if a PCC contact plow got torn off when meeting a chain remnant stuck in the slot). This all ended when our all-knowing Congress decreed the demise of D.C. streetcars in the early 1960s (1963 or 64, forget which).
The high fidelity audio transformers were really works of art, trying to get a high magnetizing inductance for the low frequencies and low leakage inductance for the high frequencies. Direct coupled outputs are so much easier.
- Erik
None of the power transformers I designed were large than 1kW. So 98% was about the best we couild do. This was 1952-1954, when some of the more exotic metals and techniques were still in the future. Alos, we produced pulse transformers requiring extremely high hihg-fruency response, and we deliberately introduced loss--producing air-gaps to linearize the frequency response. Also, conventional, but very high-quality, high-fidelity audio transformers for the tube-type power amplifiers of the time.
daveklepper There would seem to be some loss in efficiency by tranformer-like inductive coupling. At one time in my life I worked for Mystic Transformer Co., Winchester, MA, and we designed transformers to have as close coupling as possible between the primary and secondary coils. Even then, 98% was about the best we could manage.
There would seem to be some loss in efficiency by tranformer-like inductive coupling. At one time in my life I worked for Mystic Transformer Co., Winchester, MA, and we designed transformers to have as close coupling as possible between the primary and secondary coils. Even then, 98% was about the best we could manage.
What was the size range produced by Mystic? And how much of the typical loss was due to core loss (eddy current and hysteresis) versus conductor loss? I have a recollection of reading about distribution transformers attaining 99+% efficiency at rated load by using tape wound hypersil or metglas to reduce core losses. I would assume that the tape wound core would have a lower reluctance (higher effective permeability) than a laminated core. The 98% efficiency agrees with what I've read and have been told about conventional transformers.
I did come across a Westinghouse article from 1918-19 where the author claimed over 99% efficiency with a power transformer. They went on to explain that this was an autotransformer...
Power transformer design is easy when compared to designing an audio transformer capable of covering 20 Hz to 20 kHz.
Close coupling is not possible with one coil on the vehicle and the other buried below ground. I'd say about 80% efficiency is about the best that could be obtained, and this means sufficient power loss.
The 80% figure may be optimistic.
It is possible to get good power transfer with loose coupling by having a low loss source of reactive power (e.g. really good capacitors), see the section on coupled resonators in the ARRL Handbook (formerly The Radio Amateur's Handbook). this efficiency is very sensitive to disturbances in the resonant circuits such as caused by the changes in inductance due to changes in car/ground separation.
The route is the verb Rokhave (present tense) or Rakhav (past tense) or lirrkhove. infinituve, to follow. The chariot "rachba" or rachva comes from the fact that the chariot follows the horse or horses. (Soos, soosim) Thus horse and rider were thrown into the sea (The Exodus story) Sus virakhba samu baYam. And Rakevet is a faminine noun. The plurel is Rakevot. Kal is masculine for light and Kala feminine.
Still waiting for someone who had read Issue 80.
There would seem to be some loss in efficiency by tranformer-like inductive coupling. At one time in my life I worked for Mystic Transformer Co., Winchester, MA, and we designed transformers to have as close coupling as possible between the primary and secondary coils. Even then, 98% was about the best we could manage. Close coupling is not possible with one coil on the vehicle and the other buried below ground. I'd say about 80% efficiency is about the best that could be obtained, and this means sufficient power loss.
daveklepper HaRakevet means The railway or railroad in modern Hebrew, with Rakevet HaKala meaning The Light Railway. If anyone wishes to subscribe, you can easily the web address or contact me at daveklepper@yahoo.com and I will provide the information. But if anyone reading this is currently a subscriber, and has read or has issue No.80, please contact me. Thanks! The system referred to by the Jerusalem Post was not the conduit system but a surface contact system with the conducting strip about two milimeters above the pavement surface and control boxes that sense when a rail vehicle is directly above and that powers the segmant only when the car is directly above.
HaRakevet means The railway or railroad in modern Hebrew, with Rakevet HaKala meaning The Light Railway.
If anyone wishes to subscribe, you can easily the web address or contact me at
daveklepper@yahoo.com and I will provide the information.
But if anyone reading this is currently a subscriber, and has read or has issue No.80, please contact me. Thanks!
The system referred to by the Jerusalem Post was not the conduit system but a surface contact system with the conducting strip about two milimeters above the pavement surface and control boxes that sense when a rail vehicle is directly above and that powers the segmant only when the car is directly above.
Johnny
Cinders, not salt, was the curse or the saving grace on snow and ice for most of the 19th and half the 20th Centuries. As the use of coal fell, so did the availablity of ashes or cinders. And the increased reliance on salt and salt products. I don't think D.C. had that much snow and ice that salt had that much use in the city. Salt became much more prevelant as it was found in more accessble pockets than before.
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New York also had a conduit system in Manhatten. But I don't think salt was as widely used during most of the trolley era as it is today. I know, for example, that Milwaukee WI didn't start using it extensively until the last years of the North Shore Line. Unfortunately for NSL, the salt impregnated the 3rd rail pickup apparatus and caused problems on the 'L' in Chicago when the trains switched to 3rd rail pickup. Apparently, NSL had to deal with this after snowstorms by hosing down the trucks of southbound trains at Harrison Street in Milwaukee, just after they left the streets.
The "Primove" system would work better with grass (and be generally safer) than an exposed contact conductor. The initial cost is likely to be much higher than overhead wire and be less efficient as well.
What might make sense is a hybrid approach, overhead wires in most areas, with the "Primove" used in esthetically sensitive areas.
daveklepper In the 9 December magzine section of the Jerusalem Post, a reporter said that use of ground contact as developed by Bombardier would have saved money be eliminating the need for the overhead wire, as well as improving esthetics next to the Old City Wall. I wrote the Post Letters Editor and the reporter with the correction, noting that ground contact systems are more expensive becuase of the complicaton in track construction, plus the need for maintenance and inspection of the automatic devices that power the segmented rail only when the rail vehicle is over the segment. I also pointed out that the system isn't applicable to the area next to the Old City Wall, because this area is grassed, including over the ties between the rails, and there are trees as well. Wet grass and fallen leaves to not make good insulators! The track would have to be paved, with a net esthetic loss in my opinion. The reporter said she doesn't claim to be an expert. But she did accept a freebe trip to Germany to see the new Israel Railways double-deckers under construction at a Bombardier plant there. So far, no correction has been printed.
In the 9 December magzine section of the Jerusalem Post, a reporter said that use of ground contact as developed by Bombardier would have saved money be eliminating the need for the overhead wire, as well as improving esthetics next to the Old City Wall. I wrote the Post Letters Editor and the reporter with the correction, noting that ground contact systems are more expensive becuase of the complicaton in track construction, plus the need for maintenance and inspection of the automatic devices that power the segmented rail only when the rail vehicle is over the segment. I also pointed out that the system isn't applicable to the area next to the Old City Wall, because this area is grassed, including over the ties between the rails, and there are trees as well. Wet grass and fallen leaves to not make good insulators! The track would have to be paved, with a net esthetic loss in my opinion. The reporter said she doesn't claim to be an expert. But she did accept a freebe trip to Germany to see the new Israel Railways double-deckers under construction at a Bombardier plant there. So far, no correction has been printed.
Dave the reporter may have misunderstood the system that Bombardier was proposing. The Bombardier sytem "Primove" uses contactless inductive power transfer rather than a underground contact rail
Bombardier Primove
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