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WEIGHING A LOCOMOTIVE
W H E N a railroad is to buy
a new locomotive there
are three questions considered
before the purchase
is made. These are:
the weight, the distribution of the weight
and the effect of the weight upon the
tracks and bridges.
The first question is, apparently, not
hard to answer as the dead weight may
easily be ascertained by placing the locomotive
upon a huge scale. However it
is important that this weight be so distributed
that the rails, the roadbed, its
bridges, culverts and other structures
will be able to withstand the stresses imposed
by the modern locomotive in
motion. Each wheel of the locomotive
the distribution of the pressures on the
roadbed. This variation of the weight
also affects the adjustment of the springs
of the locomotive.
To ascertain the various weights
which go to make the total weight of
the locomotive a special scale has been
designed. In order to determine the proportionate
bearing value it requires one
scale for each locomotive wheel as
shown in the accompanying photograph.
At the end farthest from the scale
beam a heavy main lever projects beyond
the frame a sufficient distance to catch
IN ORDER TO DETERMINE EXACTLY THE WEIGHT DISTRIBUTION. EACH WHEEL HAS A
SCALE OF ITS OWN
bears its due proportion of the weight
and therefore each wheel has a direct
relation to the stress placed upon the
roadway.
Engineers have found that the bearing
weight over each wheel varies greatly,
even on opposite wheels attached to the
same axle, so the dead or axle weight of
the locomotive as taken on the ordinary
scale would not be a criterion in testing
4S6
under the wheel and permit the weighing.
Here a pivot is set for receiving
the wheel, the frame bears upon the base
of the rail at which point all of the
weight is concentrated. By turning the
hand wheel located below the beam upward,
the bearing pivot can be placed to
its lowest position and pushed under the
wheel. The frame, bearing upon the rail,
is leveled by the other hand wheel.