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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255
501. To determine the effect of bearing area upon the mean co-
efficient of friction, the mean value of the brake shoe bearing area
throughout the stop is necessary, rather than the total and relatively
high value observed after the stop. Obviously, it was impossible to
measure the instantaneous brake shoe bearing area continuously, and
therefore the data can be considered only as relative.
Fig. 153.
BRAKE SHOE BEARING AREAS—PLAIN SLOTTED SHOE.
502. A study of the data in a general way shows that the greater
the pressure per square inch of bearing area, the lower will be the mean
coefficient of friction.
503. The temperature observations taken as described in para-
graph 482 cannot be used to establish a definite relation between the
temperature of the working metal and the mean coefficient of friction,
for the actual temperatures existing at the bearing area were not deter-
mined.
504. The readings indicated only the temperature of that por-
tion of the shoe surrounding the pyrometer element. If this portion