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about either prototype or model trucks, so they just find the
subject confusing. What follows is an attempt to impart more
information and reduce the confusion.
To keep things from getting totally out of hand, I've given only a
sketchy account of truck development before 1900, since very
few modelers focus on railroading in the 19th century. I've also
stopped short of discussing roller bearing trucks, apart from
some very early experiments, because they are of no interest
to steam and transition era modelers like me and also because
I know relatively little about them; that's a subject for someone
else (any volunteers?).
Some truck basics
Almost all of the trucks described below had solid brass or
bronze journal bearings, also known as plain bearings. Note
that plain bearings should not be called "friction" bearings, a
term coined by roller bearing manufacturers to imply (falsely)
that roller bearings had no friction. Though not used in the
prototype railway engineering literature, the term has, unfor-
tunately, been picked up and employed by some modelers and
model manufacturers. More on this later.
Unlike roller bearings, which are lubricated and sealed, plain
bearings were open at the bottom and were crudely lubricated
by oil wicked up onto the bottom of the axle journal by cotton
waste packing. This packing required periodic replacement,
and oil had to be added to the cellars at the bottom of the
journal boxes frequently – typically every time a car stopped at
a major freight yard or junction point.
Without getting overly technical, a word about truck capaci-
ties. The vast majority of freight cars built in the first half of the
