COTTON BELT RUNS A
Blue Streak
QUOTE: Originally posted by Alaskaman Wheel starts to slip when power applied to it is greater than it can pull or the wheel spins faster than the speed of train (does this make sense?) That's loss of adhesion. >> yes, it does. a wheel slips when the load is too heavy, or the engine is too lite.. adding more weight to locomotive wiil help reduce adhesion. That's why cement is added to slugs -to improve adhesion.
QUOTE: Originally posted by PNWRMNM PRACTICAL DEFINTION IS THE RATIO OF DRAWBAR PULL IN POUNDS TO LOCOMOTIVE WEIGHT. IF 250,000# UNIT PULLS 50,000 # RATIO IS 50/250 OR 20%. ADHESION ACTUALLY OCCURS WHERE THE WHEEL MEETS THE RAIL, AND IT IS A PHYSICS PROBLEM. SIMPLEST WAY TO SEE WHAT IT IS FOR A PARTICULAR UNIT IS TAKE PULL AT MINIMUM CONTINUOUS SPEED, WHICH IS LIMITED BY ADHESION AND DIVIDE BY WEIGHT AS ABOVE. ADHESION IS VERY SENSATIVE TO ENVIRONMENTAL FACTORS. DRY RAIL IS ABOUT 25%. WET RAIL 17%. SAND ADDS 8%, SO SAND ON WET RAIL IS ABOUT EQUAL TO DRY RAIL. THESE FIGURES FOR DC TRACTION MOTORS. AC TRACTION MOTORS RATED AT 33%, PRESUMABLY ON DRY RAIL. MORE WEIGHT DOES NOT GIVE MORE ADHESION, IT GIVES MORE PULL WITH WHATEVER ADHESION IS. MAC
She who has no signature! cinscocom-tmw
QUOTE: Originally posted by ironken Hey mudchicken, on a side note, we just had a roadmaster get sent home and had to pee and blow. Seems that he copied track and time wrong, problem being that he was hauling some brass around when he did this. One of the heave duty officials asked to see his T&T and woops, went outta the limits. Bye bye! Bummer for him, he was a cool dude. Bad gig. On coming trains are unforgiving as you know. One of my worst fears is to hear the infamous, "secure your train, the trainmaster will be there to talk to you soon with your relief crew!" from the dispatcher. Ken
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