--- In BRHSlist@egroups.com, amtrak347@a... wrote:
> 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
BOB;
THE X/O LIMITS WERE 50mph FOR LIGHTWEIGHT CARS HANDLED BY DIESEL
ENGINES, SPECIFICALLY TRAINS 21, 22, 23, 24, 44 AND 49; THE LATER TWO
BEING THE EMPIRE BUILDER. ALL OTHER TRAINS WERE 40mph, BOTH
PASSENGER AND FREIGHT.
IF ANYONE WANY A COPY OF THIS LACROSSE DIV TT, SEND ME YOUR ADDRESS
AND I'LL SEND A XEROX COPY.
THERE IS ALSO INFO ABOUT MARS LIGHTS THAT MIGHT BE USEFUL TO SOME.
BRAD
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