Re: Reading USRA Gondola Load


Richard Hendrickson
 

On Jan 2, 2012, at 5:16 PM, Scott Seders wrote:

What was it about K brakes that was causing wrecks?
Scott, AB brakes were more responsive than K brakes, so they set up
faster. No problem if all the brakes were K or all were AB, but
between ca.1933, when AB brakes were mandated on all new cars (and
often applied to older cars when extensively rebuilt) and 1953, when
K brakes were outlawed in interchange, a typical train would have
some K brakes and some AB brakes (more K brakes in the '30a, more AB
in the postwar period). When the engineer set the air, the brakes on
the AB equipped cars set faster than those on the K equipped cars
and, depending on where they were in the train,
coupler slack would either run in or out. As a retired Cajon Pass
"hill engineer" once told me, "going down the 3% with a steam
locomotive, even with the retainers set up, you had to set a lot of
air, and then you'd look back and watch the slack run in and out like
a yo-yo as the AB brakes set first and then the K brakes." During WW
II, all of the major railroad downgrades were littered with broken
knuckles, drawbars, etc. as a result, and sometimes the results were
even more serious. Handling the air on downhill mountain grades was
an art form, one that flatland engineers never had to learn, and many
a train went into the ditch behind an engineer who hadn't mastered
the art.


Richard Hendrickson

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