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56528Re: Wheel/coupler combinations

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  • David K. Smith
    May 2, 2008
      Alan--

      In some circles, the Wahl Clipper oil subject will raise some heated
      arguments. Some swear by it. Others swear over it. A buddy of mine
      and I have been running his (huge) N scale layout together for over
      35 years. He tried the Wahl oil once, and it took months to recover
      from the disaster. A tiny amount of oil produced an incredible mess
      that spread everywhere, even to areas where the oil was not applied.
      It knocked the heck out of the pulling power of every locomotive (it
      will destroy most traction tires, too), and it became a magnet for
      dust and dirt.

      After decades of running trains for long periods of time, we have
      never seen any noticable amounts of wear on plastic wheels. Delrin is
      a very tough, slippery plastic, and model cars are so very light,
      that wear is virtually non-existent. Arguments have arisen over what
      constitutes the gunk that collects on the wheels and track. We have
      analyzed the gunk and found that it's ordinary household dust and
      dirt, which is bound together into the familar gunk by a combination
      of the thin, slightly oily residue present on the surface of Delrin,
      small amounts of lubricant released from locomotives, and humidity in
      the air.

      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.

      We have found that plastic wheels accumulate more gunk than metal and
      have concluded that this is due to a small static electric charge
      that can build up from the friction between the plastic wheels and
      the metal rails, particularly on curves where one wheel is always
      slipping a tiny amount. The static charge on the plastic attracts
      dirt, and over time it builds up into a layer of gunk, which is
      sometimes deposited back onto the rails. Metal wheels do not
      accumulate a static charge, and thus don't accumulate much gunk,
      except what they pick up from the rails by friction.

      Some modelers swear by certain rail cleaners that the makers claim to
      be electrically conductive. There is no cleaning solution made that
      is even the slightest bit electrically conductive--we've tested a lot
      of them. The claims of being electrically conductive are all bogus.
      Claims that the cleaners improve electrical conductivity are correct,
      but only by virtue of the fact that the rail is being cleaned;
      anything that cleans metal will improve conductivity--even a
      fingernail, for that matter.

      Scratches in the surface of the rails are claimed by some to degrade
      conductivity, which is the basis for warnings against using abrasive
      blocks. But, if you examine brand new rail under high magnification,
      you'll see that it already looks badly scratched--this is due to the
      mechanical process of drawing wire into rail. Abrasive blocks don't
      make anything worse. Some modelers will polish rail with polishing
      compound, but the polishing compounds tend to leave residues behind
      that make the gunk buildup problem worse.

      Some brands of track are said to perform better than others, and it
      appears this is true. "Nickel-silver" (which contains no silver,
      actually) is a mixture of various metals, and the proportions of the
      different metals can affect electrical conductivity, oxidation rates,
      and the tendency of the rails to accumulate dirt. Different brands of
      track will have different metal composition--sometimes you can even
      see variations in the color. Thus, different brands of track may
      perform differently.

      After decades of running, experimenting and testing, we've found the
      best way to clean wheels is by just moistening a paper towel with
      alcohol, laying it on some flex track, and rolling cars back and
      forth over it. To clean track, we just wipe the rails with a block of
      soft wood. Solvent cleaners just tend to make a mess, abrasive blocks
      are overkill and also leave abrasive debris behind, and most
      commercial track cleaners built into freight cars are ineffective.

      Food for thought!

      --David

      http://jamesriverbranch.net/
      http://1-220.blogspot.com/


      --- In z_scale@yahoogroups.com, "Glen Chenier" <glen@...> wrote:
      >
      > --- In z_scale@yahoogroups.com, Alan Cox <alan@> wrote:
      > >
      > > On Fri, 2 May 2008 10:38:10 -0400
      > > George Evans <gevans@> wrote:
      > >
      > > > Again i am new to this hobby. What is wrong with plastic wheels?
      > >
      > > They don't run on the track as well as metal ones, they also
      gradually
      > > leave tiny amounts of plastic residue on the track which is a
      real
      > pita to
      > > remove.
      > >
      > > Its a big deal if run a large exhibition layout where the trains
      run
      > many
      > > miles (real not scale) in a day but hardly a big problem for a
      small
      > > setup.
      > >
      > > Alan
      > >
      >
      > And the plastic wheel residue tends to build up in clumps at rail
      > joints. Don't know why, maybe the residue collected on the wheel
      > treads gets jolted off at the joint bump. This happens in all
      scales,
      > metal vs plastic is an often discussed topic on many forums.
      >
      > Has anyone ever compared plastic buildup with and without Wahl Oil
      on
      > the rails? The plastic wears most on curves, the fixed axle and
      > unequal rail circumference means that the wheels are always
      scraping on
      > the rail slightly rather than completely free-rolling, even with
      the
      > angled tread profile. A Wahl Oil film may (or may not) reduce
      plastic
      > wear due to rail scraping.
      >
      > Would be an interesting experiment...
      >
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