The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1900-03-09
SPEED OF a LOCOMOTIVE
DETERMINED BY JOSEPH GRAY
kITCHELL By PHOTOGRAPHY.
The Result Was Used as In a
Lawsuit-A Technical Descrip-
ton OF the Method.

A photograph of a train in rapid motion
was recently taken by Mr.. Joseph Gray
Kitchell, of this city, in New York State.
to determine the rate Of speed for evidence
in an important lawsuit.
The picture was made with the most
approved apparatus and sensitive plates
and the result was a wonderfully graphic
illustration and the speed determination
was computed TO a scientific nicely. AS
his was probably the first time photo
graphy was ever used TO record locomotive
speed. the details may be of interest to
photographers and others, Mr.. KitchelIs
claim for originality, however, being only
in the method Of computation discovered.
The print from the negative was perfect
ly sharp save in one particular. Although
the train was moving at the rate of 62 1t
miles an hour, the blurred exception ex-
hibiting motion was made use Of on which
to base the speed calculations. The pho
tographic particulars Mr.. Kitchell de-
scribed as follows: 'Lers, Goerz, sx1O F.
II; shutter, b. & L., diaphragm wide open,
set at LOO of a second; plate, Seed % Sen;
camera placed 200 feet from focused point:
diagonal plane of plate to plane of track,
12o degrees.
"It being approximately estimated that
the train would be moving at a rate ex-
ceeding a mile n minute the shutter was
set accordingly to catch 1t at practically
a standstill. Thus the exposure would
nave to be made in 1-SS of a second or less
as a body moving a mile In a minute passes
through IS feet of space in a second, thus
the shutter was tested to an i~nstantane-
Gus exposure of only loo of a second.
The chief factor of interest and of value
lay in the detail that the entire image of
the locomotive was perfectly sharp as
though it were at rest except the spokes
of the driving wheels describing a half
circle superior to the horizontal line drawn
across the center of the main axles, the
spokes being more blurred in ratio TO their
proximity TO the center vertical line at
the point Of the most superior periphery
of the wheel. The reason for this was in
the fact that these upper spokes travel
through space at a higher forward rate
of speed than the lower ones. This would
appear to be erroneous until it is under
stood that all parts of the engine are COW
ering the same distance on the track in
a given time. yet the upper parts of the
wheel have the same general unit of for
ward motion plus the individual forward
motion of revolution, and the lower parts
of the wheel, having the same general
forward motion, but retarded in their for
ward progress by thrust that
begins at the middle forward horizontal
point and ends at the middle horizontal
posterior point. A simple illustration of
this may be obtained in a spectacle of two
brakemen running along the top of a
freight train in contrary directions, the
enc advancing in the direction Of train
progress moves through space at a higher
rate of speed than the one receding from
the direction Of train progress.
Now. by carefully measuring the ex-
tent of motion evidenced by the sphere of
blur made by the upper spokes in the loo
part of a second and comparing with the
stationary impress of the lower spokes a
ratio of difference in the given time is
established and one that may be used as an
hypothesis, which, computed with the
known diameter and other measurements
Of the driving wheels, will indicate the
speed per second, minute or hour"