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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290
(a) The only difference between the UC pneumatic and
electro pneumatic emergency application is in the elimi-
nation of the time element in starting the application of
the brakes on the various cars in the train. (Par. 197.)
(b) The effect of the time element in the serial action of
brakes operated pneumatically is to produce shocks,
especially when emergency stops are made from low
speeds. Emergency stops with the electro-pneumatic
equipment, in which serial action is eliminated, are free
from shock except that due to the difference in braking
power between the locomotive and the cars. (Pars. 424
to 428.)
5. Smooth stops can be made with the UC equipment with grad-
uated release and its use results in a saving in air, time and distance
in making the stop. (Pars. 219, 223.)
6. An analysis of the operating features of the PM and UC equip-
ment shows that:
(a) The results obtained with the UC equipment (PM features
only) are substantially equivalent to those obtained with
PM equipment. (Par. 191, Fig. 93.)
(b) After the train is charged, should an angle cock be closed,
the operation of the electro-pneumatic equipment is not in-
terfered with for a single application, either service or
emergency. (Par. 238.)
(c) With the PM and UC equipment for full service applica-
tion on a 12-car train, the following table shows the
average time of starting an application on the first car,
on all cars, and the time to attain full brake cylinder
pressure:
Equipment Brakes Start to apply on Full brake cylinder pressure ATTAINED
1st CAR 1 Sec.. 3 Sec.. 3 Sec.. All cars
PM UC Pneumatic.- UC Electro-Pneu- matic.. 3 to 4 Sec,.... 5 to 6 Sec 3 Sec 12 Secs. 16 Secs. 9 Secs. Fig. 44. Page 76 Fig. 44-A. Page 115 Fig. 44 A. Page 115
From this it is observed that when using the pneumatic
features only with the UC equipment, the time of start is
later on all cars than with the PM equipment and the
attainment of full brake cylinder pressure is 33 per cent,
later. The slowness of starting the service application
with the UC equipment does not affect the time of com-
mencing to obtain an effective braking force (Par. 160),
but does serve the desirable purpose of protecting the