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56535Re: Wheel/coupler combinations

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  • David K. Smith
    May 3, 2008
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      True, I don't run these locos any more (although I used to have a few
      of them). But my point is that the carbon present on the wheels and
      rails is not a result of electical arcing between them, as some
      contend. Carbon can certainly be present from other sources, such as
      armatures. It is doubtful, however, that the arcing of the armature
      is involved with the actual production of the final gunk mixture, as
      this would mean the armature is filled with dirt, oil and the other
      components of the gunk, which is unlikely; the gunk is more likely
      still being produced by a mechanical process involving the friction
      of wheels and rails, and acquires carbon thrown off of the armature.
      And the higher voltage required by this loco is more likely a result
      of its age and design.

      --- In z_scale@yahoogroups.com, "viktor_kovacs" <viktor_kovacs@...>
      wrote:
      >
      > --- In z_scale@yahoogroups.com, "David K. Smith" <david@> wrote:
      > > Some modelers claim the gunk contains carbon as a result of
      > > electrical arcing. This is physically impossible as there is no
      > > source of carbon: rails are nickel, and wheels are nickel, brass
      or
      > > plastic. No carbon in them, or in the atmosphere; plus, there
      isn't
      > > enough current present to produce much in the way of arcing
      (we've
      > > only seen some slight arcing at dead shorts, and none during
      normal
      > > operation). About the only place you'll see actual carbon
      deposits in
      > > a model railroad is on motor armatures, which is being worn off
      of
      > > the compressed carbon brushes by friction.
      >
      > Your oppinion clearly indicates that you don't really run old
      > small marklin locos on your track. The br89 and a few other
      > engines have their motor fixed in a vertical position. The design
      > is that the motor sucks air (and dust) from below and hot air
      > leaves through the windows. The position of the motor results
      > in a situation that the brushes are mounted below the motor,
      > very close the rails and don't have anything below them. You
      > can actually check the condition of the brushes by turning the
      > engine upside down. All carbon dust that falls off the brushes
      > goes directly onto the track. These small locos also tend to
      > arc a lot, especially the old 8800 series, where the starting
      > voltage is much higher than on modern ones, so sometimes
      > you have to give 5 volts to make the loco run, while most modern
      > motors start to turn above 2.5-3 volts. Personally I see three
      > sources for gunk: household dust, carbon from the engines,
      > oil dripping from the open geartrains and all this mixed together
      > by the arcing of the locos. Since I don't use plastic wheels,
      > they can't contribute to dirty track. (metal wheels tend to derail
      > less, cut switches easily and sound much nicer)
      >
      > For cleaning I use a lens cleaner cloth. This is a nonabrasive way
      > to get the rails clean and if chemical cleaning is required, pure
      > alcohol is usually more than enough. The only important thing is
      > to make sure the inner vertical edge of the railheads are clean
      > too, since many locos use it for electrical pickup in curves.
      >
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