My comment in reference to the 50 MPH crossover speed limit deals with
"contemporary" railroading versus "the good old days", 46-53 or more years
ago. Electric-straight air equipped diesel-powered passenger trains were
"special", experimental and short-lived trains. Brad, what were the P/F
crossover speed limits at the locations named in your LaCrosse Division TT
for normal trains?
I remember talking with several "old timers" and Karl, about the "Northerns"
equipped with electric straight air. Then, as now, when an engineer applied
the train brakes, air exhausted (made noise) in the cab of the locomotive.
With electric straight air, there was no "exhaust" aka "noise" in the cab, as
brakes were applied "electrically" on each car. Trainline pressure was not
reduced to apply the brakes as with the typical brake system. Locomotive air
gauges would not register a reduction in ER and BP pressures in the
"electric" braking mode, except for an increase in BC pressure, which in
almost all cases, was "bailed" or "actuated" off to keep the train slack
stretched. Most "old head" engineers made their brake applications "by ear",
with less reliance on their air gauges. Factor in the "electric mode" with
no noise and no gauge movement and immediately the engineer assumes "a
braking system failure" and switches his brake system (24RL on the E-units)
to standard automatic braking and opening the "electric air" circuit breaker.
Upon arrival at the terminal, the Mechanical Dept. would spend hours on end
trying to determine the reason for the failure reported by the engineer.
"Down-time" on this equipment brought about its demise. The purpose of
electric straight air was to give the engineer better control of his train
with a faster, uniform application and release of the train brakes throughout
the length of the train that was associated with high speed passenger trains
at the time. I believe, as time wore on, the "engineer" problem was solved,
but the specialized control valves, cables and the like, began to show their
age and "true" failures of the system occurred. I found it interesting to
read that the Southern Pacific was an early developer of an improved braking
system for their "Daylight" passenger trains back in the 30's, where they
devised a system (HS-8?) that applied the brakes from the rear of the train
and braking advanced, serially, towards the front for better control of
slack. The "Q's" E-units had a two-position lever on the side of the 24RL
brake stand that switched the braking system from either SA (straight air)
for use on commuter trains, to AU (automatic air) for conventional braking.
Conventional automatic air braking was required in suburban service, when
there was more than one unit powering the train (Karl, remember the "Rosie"
Greer story?). The only drawback to conventional air braking on the 24RL
equipped "Q" units was that they lacked a "pressure maintaining" feature in
the "lap" brake handle position. The GN and NP passenger "F's" did have this
feature (trying to find the cut-out cock for it, was another story!) but
trying to figure out in what brake handle position (either first service or
lap) the "feature" worked in was a chore as each loco varied from one to the
next. Suburban straight air lasted 'til the MK rebuilding in '73(?) when the
24RL brake schedule was replaced the WABCO PS-68 schedule which was an
electrically "assisted" brake system (it left a lot to be desired!).
Excuse the length of this post. I was thinking of throwing in my "two-cents"
worth about Mars lights, but I'll pass for the night.
Bob Campbell
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