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Ground contact vs. overhead wire

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Posted by daveklepper on Wednesday, January 11, 2012 3:27 AM

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.

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Posted by Paul_D_North_Jr on Thursday, January 12, 2012 5:27 AM

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.     

"This Fascinating Railroad Business" (title of 1943 book by Robert Selph Henry of the AAR)
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Posted by Skip Lackie on Saturday, January 21, 2012 8:14 AM

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.

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.

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Posted by narig01 on Saturday, January 21, 2012 9:44 PM

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

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Posted by daveklepper on Wednesday, January 25, 2012 3:30 AM

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.

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Posted by aegrotatio on Sunday, January 29, 2012 9:11 PM

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.

 

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Posted by aegrotatio on Sunday, January 29, 2012 9:15 PM

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.

 

 

 

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Posted by The Bernie on Monday, February 13, 2012 8:30 PM

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

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Posted by daveklepper on Tuesday, February 14, 2012 3:53 AM

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.

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