Dave H. Painted side goes up. My website : wnbranch.com
QUOTE: Originally posted by dehusman The limit was not MU signal degredation but tractive effort/braking power limits. It you get too many units working then you have enough horsepower/braking power to damage the train with too quick speed changes. A typical limit was no more than 8 units on a train. Dave H.
Thanks to Chris / CopCarSS for my avatar.
QUOTE: Originally posted by Old Timer I'd like to know about those 9000 HP 2-10-4s. Is that figure confirmed on tests? Is it drawbar horsepower? Cylinder horsepower? As I recall, the CGW 2-10-4s were practically duplicates of those that went to the T&P, and they weren't anywhere near 9000 HP. In fact, no steam locomotive ever built ever got near 9000 HP. The C&O 2-6-6-6 was reportedly the most powerful, HP wise, and the maximum they ever recorded was 7498. Old Timer
-ChrisWest Chicago, ILChristopher May Fine Art Photography"In wisdom gathered over time I have found that every experience is a form of exploration." ~Ansel Adams
USAF TSgt C-17 Aircraft Maintenance Flying Crew Chief & Flightline Avionics Craftsman
QUOTE: Originally posted by Overdurff I wonder if it may not be so much a horsepower on the front limit, but rather more of a structural limit in the coupllers, and the frames of the cars that have to stand up under the strain of moving the train behind them! Will
QUOTE: Originally posted by Mark_W._Hemphill On railroads with dynamic-brake equipped locomotives, the maximum number of units one could M.U. in the old days of field-loop dynamic braking was four units, if you wanted to use the dynamic brakes. After 1954 or so, when point-potential dynamic brakes were developed, the old four-unit limit no longer applied on units so equipped (GP9s and F9s and better), as well as older units that had their dynamic brakes rewired to point-potential type. Into the 1970s you still saw many dynamic-brake equipped GP7s and F7s with the old field-loop selector switch still in place (but it didn't do anything) -- the switch sets whether the dynamic brake has 1, 2, 3, or 4 units. Older units that still had field-loop dynamic brakes still were limited to four units. Mixed consists required you to use one or the other, but not both, in dynamic braking -- whatever was on the point governed. Field-loop dynamic brake equipped locomotives all had an extra jumper (M.U.) cable to connect up the dynamic brake control circuits, as I recall. I'm afraid I've completely forgotten the technical information necessary to describe the difference between point-potential and field-loop dynamic braking, other than to know that point-potential was a big improvement. Those so inclined can find plenty of technically dense papers on the web by searching for the terms.
QUOTE: Originally posted by western Regarding the maximum unites in a consist. In the past on CN Canadian National the ruling was a maximum of 24 motorized powered axels on a train. This meant all units whether A, B or freight. This I believe was to avoid engines with non alignment draw bars jack knifing from slack action and that same slack action pulling draw bars.[^]
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