One reason for not hearing slack when starting is as a policy we try to stop with the train stretched.It allows for a smooth start for one and two keeps the malcontents from being able to pull the pin on you.
You now things are going good when you start up and as soon as the motor starts to move old fred gives a beep and says hes moving too.
Yes we are on time but this is yesterdays train
....So it sounds to me {from the last statements above}, the act of coupling / uncoupling process relies more on slack in the operation of a train than does slack being used to start a train.
Does slack give starting a mile long train that much advantage when it only provides 50' or so to work with....Watched a 5 engine train on the Frankfort line here start last night {and didn't hear any slack...being taken up}, must have been stretched...{and just 2 of the engines were on line}, so that {the other 3}, were added dead weight....but it is level track here from where we watched...But it sounded like the engineer just notched lightly to start.....as he was to proceed slowly...{heard it on my radio}, so the diamond at CSX could be cleared by the time this train arrived there...just a mile or less ahead. Guess I'm saying the train seemed to move out very easy without using "Slack".
Quentin
The tolerance issue notwithstanding, another use of slack that has gone by the wayside was using it to start a long, heavy train.
Before high horsepower, DP, and roller bearings, trains would often be started by bunching up the slack (while stopping, if possible), then pulling it out. The locomotive only had to start one car rolling at a time (albeit in rapid succession). I've been around trains when you could hear the slack action coming and going from your vantage point mid-train.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
.....Do they {by design}, get away with less slack on passenger trains simply because they are shorter and less tonnage...?
One would sure think it would be less difficult to operate a train {freight}, if less slack was "built in" to couplers, etc...
Does today's tonnage and power combination allow operation of a long freight train {if less slack was the condition}.....?
Is it a fact slack is benificial to getting a train started in some instances....?
One would think {by looking at the design}, the Triple Crown type trains have quite a bit less slack than normal rail cars consist has....but understand it is much less tonnage too...
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I would say slack is a nessasary evil in couplers for longevity. If the tolerances were tighter they would probably have a much shorter lifespan and thus higher maintainance costs. just my 2 cents.
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