Re: Repack question


Bill Daniels <billinsf@...>
 

Bill,

Repacking of journal bearings was usually done on a 24
month cycle. The process was that the journal box was
jacked up under the cellar and the packing material
underneath the journal bearing, (cotton waste or more
likely later on a specially developed pad,
unofficially
refered to as a "Kotex") would be removed and
replaced. The
bearing surfaces would be inspected for damage. The
axle
would then be dropped while the new packing material
would
then be oiled. This was done on all eight (for most
cars)
journal boxes and the car would be restenciled to
reflect
the maintenance performed.

Most cars were checked for oil on a almost daily
basis...car knockers would carry a can of oil while
inspecting inbound trains at a yard, lift the cover
and add
oil if needed.

The pad was developed due to the fact that sometimes
due to
hard coupling the bearing would lift off the journal
surface on the axle and a string of waste sometimes
would
get lodged under the babbit metal. This would lead to
oil
starvation on the bearing (the oil would form a wedge
and
be the actual load carrying surface on which the load
was
carried) would "wipe" causing bearing failure
(hotbox).
Another cause of bearing failure was the fact that
bums and
transients would remove the waste to use to start
fires at
night.

Interestingly enough, most of the time at speeds
greater
than 15 mph, a conventional journal bearing had the
same
rolling resistance as a roller bearing. But the higher
maintenance requirements, constant oil leakage on the
face
of the wheels (ever notice that all wheel faces on
conventional bearing eqipped cars were dead black?)
and
cold weather resistance (due to higher oil viscosities
in
cold weather) at low speeds (as well as the other
points
mentioned above) led to the eventual banning of
conventional bearings in railroad use. However, they
are
still used today in many applications.

Please note that I do NOT refer to these bearings as
"friction" bearings (there ain't no such thing) This
was a
slander that was due to the direct advertising efforts
of
the Timken Company to bad mouth these bearings. I once
met
a engineer who worked for Timken and he confirmed that
this
was the case.

Bill Daniels
Tucson, AZ

On Wed, 01 Jan 2003 11:12:20 -0500
Bill Lane <billlane@comcast.net> wrote:
Hi All,

If a car was shopped (Painted etc) 10-55, how long
would
it be out on the
road before it gets repacked again? Would this be
simply
adding oil, or
disassembling the trucks for bearing maintenance?
Does
the type of car make
a difference in this? How is this tracked? Finally,
the
main question is,
what would the time frame have been from a paint
job, to
it's first painted
repacked date?
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