Page 92 - 39. MRH13-05-May2013
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68: The simplest way to get roller bearings was to
retrofit them in existing trucks, as the Union Pacific
did on their DLS stock cars. As the bearings were
invisible inside the original journal boxes, the journal
box covers were painted aluminum so carmen would
know not to pour journal oil into them.
68
Following the war, roller bearing manufacturers engaged in
a vigorous promotional campaign to market their wares to
the railroads, even going so far as to describe roller bearings
as "anti-friction" bearings in contrast to "friction" (i.e., plain)
journal bearings. This terminology was nonsense, of course;
all bearings have friction, and though roller bearings have less
resistance to starting and at low speeds, their advantage was
relatively slight at normal train speeds.
In any case, railroad officials weren't inclined to spend money
putting roller bearings on cars that spent much of their life
off-line in interchange, so the relatively few cars that received
roller bearing trucks were in assigned service and seldom or
never left their owners' rails. One such example was the Union
Pacific's DLS livestock trains from Salt Lake City to Los Angeles;
in this case, roller bearings were fitted to existing trucks, and
the only evidence of their presence was aluminum-painted
journal box covers (68). Another was a small number of Akron,
Freight Car Trucks - 24
69
Canton & Youngstown covered hoppers for on-line service
which came from American Car & Foundry in 1947 with roller
bearing National B-1 trucks (69).
In the late 1940s through the 1950s, applications of roller
bearings to existing truck designs continued to be relatively
isolated experiments (70 and 71). What apparently tipped
the scales in favor of roller bearing trucks was the construc-
tion, beginning in the late 1950s, of growing numbers of 90
and 100 ton covered hoppers for grain service. On these cars,
four-wheel plain journal trucks were overloaded, and they
were very prone to overheated journals, the dreaded "hot
boxes" which required them to be set out of trains at the ear-
liest opportunity while en route. Roller bearing trucks solved
69: This roller bearing National B-1 truck for was
applied to covered hoppers built by AC&F for captive
service on the Akron, Canton & Youngstown. The
side frames had pedestal jaws into which the Timken
bearings were fitted.
MRH-May 2013
