Brake Tests
År: 1913
Forlag: Pensylvania Railroad Company
Sted: Altoona, Penna.
Sider: 401
A Report Of A Series Of Road Tests Of Brakes On Passanger Equipment Cars Made At Absecon, New Jersey, In 1913
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51. This wheel sliding indicating mechanism (Fig. 10 and 11), con-
sisted of a spring motor driven drum on which was obtained the record
of five pencils actuated by magnets. Four of these were connected
to contacts arranged on the respective axles so that each magnet circuit
was made and broken once for each revolution of the corresponding
axle. The fifth pencil magnet was connected in the distance circuit
controlled by the distance machine on the locomotive so that eacli
fifty feet traveled by the train during the stop was recorded on
the drum simultaneously with the record of the revolutions on each
axle. A typical record from tlie wheel sliding indicator is shown in
Fig. 12.
52. The distance machine referred to consisted of a mechanism
driven from the engine truck wheel and having contacts arranged so
that the distance circuit leading to tlie wheel sliding indicators on
the cars was made and broken once for every fifty feet traveled by the
train during the stop. This distance circuit was so interlocked with
the trip which applied the brakes that the point of brake application
was indicated on each wheel sliding record. The instrument is shown
in Fig. 13, and its electrical connections, as related to the train test
circuits, in Fig. 9.
Kapteyn Chronograph.
53. This instrument is shown in Figs. 14 and 15, a detailed descrip-
tion of which is unnecessary for the purpose of this report. It will be of
interest, however, to note that with this instrument the following graph-
ical records during the stop were made, all on a distance base, the paper
of this instrument being driven by means of an idler running on the rail.
(a) A continuous record of speed, thus giving an autographic
speed-distance curve.
(b) A continuous record of deceleration which, to tlie proper scale
measurement, shows also the instantaneous values of the force of re-
tardation acting on the car, thus providing an autographic force-time
curve for each test.
(c) Brake pipe pressure.
(d) Distance of stop.
(e) Time of stop.
(f) Brake cylinder pressure.
54. In connection with the deceleration curve means were pro-
vided for recording the observations of the sparking of brake shoes
which were noted by an observer in car four.