--- In STMFC@..., Richard Hendrickson <rhendrickson@...>

Journal bearings were half-bearings, in effect, which bore only on the
top of the axle journal. Oil was poured into the lower part of the
journal box, which was loosely packed with cotton waste positioned so
that it wicked lubricating oil onto the lower half of the axle journal,
thus providing continuous lubrication. The workmen who added oil to
the journal boxes had hook-like tools which would fluff up and
reposition the cotton waste packing. Eventually, however, the waste
would pack down and accumulate dirt, so it had to be changed
periodically, usually about once a year. This is what was meant by
journal repacking and, because it was required at more or less regular
intervals, that's why the repacking data was stenciled on the cars.
Journals were also repacked, of course, if a wheel set had to be
changed out or if one or more journal bearings required replacement.

Richard Hendrickson

But the real reason is...

Actually, Richard has it right, except he didn't conclude with the
real reason why a journal repack was required periodically; to make
sure someone serviced the journal on a regular basis. Carmen would
inspect the journal by pulling a hooked rod along the underside of the
axle to feel if the surface was scored, then add oil as part of their
regular terminal inspection, but the requirement for a periodic repack
ensured that the old dirty waste was pulled and the box flushed clean,
and the clean journal inspected before it was packed with new waste
and clean oil. Kind of the same as the difference between adding oil
to you car and CHANGING the oil in your car. By the way, the name
"waste" doesn't mean it's dirty; it is pieces of clean cotton yarn
too short for use in weaving. In the last days of solid bearing trucks
pre-made journal pads became popular; these look like a small pillow
made of terrycloth, stuffed with yarn and sewn shut. These were less
likely to settle away from the journal, and all but eliminated "waste
grab", where a single strand would get drawn in between the axle and
brass and burn to carbon from the pressure, the hard carbon particles
then embedding themselves in the brass bearing and scoring the axle
bearing surface.

As Richard stated, solid journal bearings only covered the top 1/3 or
so of the axle; the ball of waste or pad was positioned to wick up oil
and wipe the bottom. The oil film was carried between the axle journal
and the journal brass, where it could creep out the ends. There was no
real seal at the back of the box, only a wooden "dust guard." Oil that
would creep out the back of the bearing would creep along the axle
past the dust guard, where it would b flung off onto the face of the
wheel by the rotation of the axle. That is why the wheels on steam era
freightcars are always an oily black color. Whatever dust was around
would stick to the oil, and the oil would turn it dark in color.

Dennis






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