Record of Recent Construction, No. 13. Page I
BALDWIN LOCOMOTIVE WORKS
In order, as far as possible, to facilitate the various mathematical calculations necessarily involved in
locomotive practice, the following plates have been prepared, in which, by graphic curves, demonstrated results are
quickly obtained.
Plate N o . i shows a curve representing the revolutions per mile of driving wheels of various diameters. The
diameter of the wheels is designated by the numbers at the top of the chart, and the revolutions per mile by the
numbers at the left hand margin.
A perpendicular line from any number representing the diameter of the wheel, followed to its intersection with
the curve, will indicate bv the horizontal line from this point of intersection the marginal number representing the
speed in revolutions per mile for the given wheel.
T h e revolutions per mile multiplied by the number representing the speed in miles per hour, divided by 60,
will give the revolutions per minute.
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