I remember riding once in the center-entrance 1914 Kuhlman "grease car" on the Shaker Heights Rapid Transit Lines about 1965. As I recall, a worker stood on the roof platform and held up to the wire a broom or mop-like device saturated in "grease" (probably a graphite compound) that lubricated the overhead. This car operated perhaps every 4 to 6 weeks and always in the wee hours of the morning.
Can anyone here tell me more about this seemingly antique process? Is it still done today, perhaps on Market Street or any other streetcar lines? Do light rail lines or railroads perform something similar to their overheads? What's being used? And what difference does it make?
Thanks.
I've heard of this practice in the States - (it's the trolley wire that's lubricated, not the catenary).
UK systems almost all used trolley wheels and didn't lubricate the trolley wire - Edinburgh (and others?) used carbon skid inserts (as used in trolley buses) instead of wheels which apparently caused a lot less wear.
Kind regards,
Andrew Harper
In the old days the usual trolley wheel was brass, and since it rotated, it did not wear the wire much. Then sliding shoes were the new replacement, and if brass, then the kind of lubrication you describe was necessary. (At the time of your fan trip, Shaker still had trolleypole, not pantograph, operation. Today most pantographs, all electric railroads, high speed to local streetcar, have graphite wearing trips that lubricate the wire and are replaced regularly. This is true of both the Breda cars on Shaker and the east-west heavy rail rapid transit line.
PS: I believe I was on that fantrip also!
Graphite pick up shoes and contactors has replaced probably nearly every form of electrical pick up device on the market today.Graphite is the ideal pick for electric locomotives and other mobile electric forms of transportation for many reasons....
1.) It is cheap(it is pencil lead after all).
2.)It conducts electricity nearly as good as a wire.
3.)Graphite is used a lubricant.It is similar to a dry hard stick of grease.It will slide easy against copper buss bars and catenery wire.
4.)It is lightwieght and easy to replace.
5.)Graphite will wear ten times as fast as the wire it contacts.This helps keep wire cost low as the Graphite is much softer than the wire.A brass or copper pickup sliding against brass or copper wire would be putting a nearly equal amount of wear to both the wire and pick up and wearing the wire out much more quickly.
Thomas 9011Graphite pick up shoes and contactors has replaced probably nearly every form of electrical pick up device on the market today.Graphite is the ideal pick for electric locomotives and other mobile electric forms of transportation for many reasons.... 1.) It is cheap(it is pencil lead after all). 2.)It conducts electricity nearly as good as a wire. 3.)Graphite is used a lubricant.It is similar to a dry hard stick of grease.It will slide easy against copper buss bars and catenery wire. 4.)It is lightwieght and easy to replace. 5.)Graphite will wear ten times as fast as the wire it contacts.This helps keep wire cost low as the Graphite is much softer than the wire.A brass or copper pickup sliding against brass or copper wire would be putting a nearly equal amount of wear to both the wire and pick up and wearing the wire out much more quickly.
Except that Graphite is too soft. It is a form of Carbon, and is similar to Graphite in that it does lubricate the contact wire, but it isn't graphite.
Contact wire is a special alloy of Copper and it is cold drawn to make it tougher. On system that use Copper contact strips, the contact strips use copper that is much softer.
Graphite can be made in varying degrees of hardness. What railroads or transit systems use copper contact strips on pantographs today?
daveklepperGraphite can be made in varying degrees of hardness.
Graphite can be made in varying degrees of hardness.
As can Copper, but at what point is it no longer graphite. Graphite and Diamonds are both solid Carbon. Likely at some point when the crystalline form changes.
What railroads or transit systems use copper contact strips on pantographs today?
Poland, Slovenia, and Italy (3Kv DC lines), use copper contact strips. Euro Cargo Rail Class 186 electrics had the contact strips changed from Carbon to Copper to cure a premature wear problem on French 1.5Kv DC lines. I don't know if this was due to mechanical wear or vaporization due to high currents and arcing. Note that the pan used on the DC lines is different from that used on the French AC lines, the locomotive has two AC and two DC pantographs.
I think you will find the the NEC, SEPTA. MN. LIRR, NJT, and MD all use graphite. Plus all the current LRT in North America
beaulieu Graphite pick up shoes and contactors has replaced probably nearly every form of electrical pick up device on the market today.Graphite is the ideal pick for electric locomotives and other mobile electric forms of transportation for many reasons.... 1.) It is cheap(it is pencil lead after all).
Johnny
beaulieuPoland, Slovenia, and Italy (3Kv DC lines), use copper contact strips. Euro Cargo Rail Class 186 electrics had the contact strips changed from Carbon to Copper to cure a premature wear problem on French 1.5Kv DC lines.
When crossed with an electrical current, graphite changes its properties to modify the orientation of the high density superficial graphitic planes to ease its passage across the oriented graphite layers. The basal planes of graphite surfaces crossed by an electrical current are deformed and contribute to increasing the number of junctions, which enhances the electrical conduction and that influences the tribological behaviour (the behaviour of contact surfaces in motion) of the graphite in the contact. What this means is that sources of friction are reduced as the structure is almost "melted," but not quite. It isn't melting, but rather re-orientation of molecular structure; an electrical phenomenon rather than a heat-related phenomenon.. It is a different event that only superficially resembles a liquification; i.e. resulting in a near-perfect smooth surface. This leads to much lower friction and lower mechanical wear rates in sliding electrical contacts than, for instance, if there were no electric current applied.
It is serendipitous that a cheap material like graphite responds in this fashion, and has little to do with graphite, per se, but only graphite under the direct influence of heavy electrical current.
DC systems, where the amperage crossing the graphite interface is generally much higher than in AC systems, generally use long-lasting copper strips on the pantograph, against a copper contact wire, but the liberal use of graphite grease creates an intermediate surface so that there is no copper/copper contact at all, but rather a graphite/graphite interface which has as low a coefficient of friction as can be reasonably and inexpensively generated, while at the same time offering a lower resistance than a copper/copper or copper/graphite surface and higher electrical conductivity. It is very nearly an ideal solution to what was a perplexing problem nearly 100 years ago when GE first began looking at alternatives to roller pantographs. The effect results from anisotropic behavior of the graphite molecules under electrical stress which is interesting physics all by itself.
If you have examined a contact shoe or the bottom of a contact wire where graphite grease has been used, the surface is mirror-like, and the effect of contact is akin to ice-skating. I have examined 60 year old copper contact wire and compared with measurements of 50 years earlier, found almost no discernible wear on the contact wire after the graphite grease was introduced.
daveklepper In the old days the usual trolley wheel was brass, and since it rotated, it did not wear the wire much. Then sliding shoes were the new replacement, and if brass, then the kind of lubrication you describe was necessary. (At the time of your fan trip, Shaker still had trolleypole, not pantograph, operation. Today most pantographs, all electric railroads, high speed to local streetcar, have graphite wearing trips that lubricate the wire and are replaced regularly. This is true of both the Breda cars on Shaker and the east-west heavy rail rapid transit line. PS: I believe I was on that fantrip also!
Falcon48 daveklepper In the old days the usual trolley wheel was brass, and since it rotated, it did not wear the wire much. Then sliding shoes were the new replacement, and if brass, then the kind of lubrication you describe was necessary. (At the time of your fan trip, Shaker still had trolleypole, not pantograph, operation. Today most pantographs, all electric railroads, high speed to local streetcar, have graphite wearing trips that lubricate the wire and are replaced regularly. This is true of both the Breda cars on Shaker and the east-west heavy rail rapid transit line. PS: I believe I was on that fantrip also! Trolley wheels actually wear the wire worse than a sliding shoe (even a non-graphite shoe). The reason is that a trolley wheel has much smaller contact surface than a sliding shoe. As a result, it will arc when the car is drawing power. I've seen electric cars at a RR museum with trolley wheels operating at night, and it looks like an arc welder is travelling down the tracks. The electrical arcing does more damage to the wire than the mechanical friction from a sliding shoe (which has a much larger electrical contact area). I do know, however, that electric interurbans which used steel shoes did lubricate their wire. I distictly recall seeing (several times) the North Shore line car going by with a guy standing on the roof platform holding some kind of a lubricant (probably graphite) against the wire. This was, of course, before OSHA.
I should have mentioned that the North Shore Line didn't use carbon inserts in their trolley shoes, even though they were available in the road's later years. They used steel shoes. My understanding of their reason for doing this (from a now deceased NSL employee) was that the carbon inserts couldn't handle high speed operations on directly suspended trolley wire (the NSL main line north of Waukegan,the Mundelein branch and most of the Shore Line Route had directly suspended wire), On this kind of wire, there would effectively be an impact at high speeds at every hanger, which could shatter a carbon shoe.
With proper maintencance, brass trolley wheels should NOT draw an arc. But, like with steel sliding shoes, some lubrication is necessary, with the graphic lubricant acting as a cleaning agent and protection against green oxidation. Without this protection, the presence of arcs is inevitable, and then you right, the wear is far far greater. At Branford's Shore Line Trolley Museum, I very seldom saw arcs, duirng late evening operation when they should have been visible.
But I remember one snowy evening on Pittsburgh's Evergreen line, the last non-PCC line to enter the downtown area, using double-end Perter Witt lightweights with the usual deck roof, when the whole trip was lit up by arcing.`
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