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What's so special about Big Boys?
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[quote]QUOTE: <i>Originally posted by GP40-2</i> <br /><br />[quote]QUOTE: <i>Originally posted by electro-ortcele</i> <br /><br />Ok, lets supose you have a train of 5.5 miles long. <br />That's 8.8km , or 8800 meters. <br />Let's say you have bigger cars that are 20m long, that's 440 cars. <br />Let's say each car has 60 tons loaded. That's 26400 tons. <br /> <br />The rolling resistance on horisontal terrain is about 5 lbs per ton. <br />So you'd have to apply a force of 132000 lbs to keep that train at your desired speed. <br /> <br />If you used diesels, then the amount of HP required would be: (force in lbs)x(speed)/375 and that's about diesel 22880 hp on the drawbar <br /> <br />When it comes to steamers, they act differently. The are able to sustain their starting tractive effort for a long range of speeds. <br />Big boy already had a starting tractive effort greater than 132000lbs that is required for this, but I don't think it could keep it up to 65mph <br /> <br />If Big boy could keep its starting tractive effort up to 65mph (which I doubt, but I don't know for sure), then it could indeed pull a train 5.5 miles long at 65mph. <br /> <br />But even if it couldn't, it could do the same at lower speeds. <br />Steamers have constant force as oposed to electrical transmision locomotives that have contant hp but changing( falling) force. <br /> <br /> <br />In other words, as incredible as it may sound at first, a steamer could pull much more load for the same hp because it could keep its starting tractive effort for a long range of speeds, and didn't have a minimum continuous tractive effort. <br /> <br />The reason why a single diesel can't pull 5.5. miles long trains, is not because it is too weak, but because the required trative effort could only be reached at lowers speeds which are forbiden for a DC traction locomotive because the motors would burn up. <br /> <br /> <br />[/quote] <br /> <br /> <br />Blah,Blah,Blah...A steam locomotive is not a constant force machine. I guess you and the Trainjunky never heard of steam cutoff. <br /> <br />Trainjunky; you are like an pesky little fly that buzzes around a picnic table. You post made up crap and lies all over this site, and when others tell you your little fantasy can't happen, you buzz off for a while, olny to return to bother us WITH THE SAME CRAP AND LIES. <br /> <br />No go and fly off and eat some dog poop. <br />[/quote] <br /> <br />Dear GP40-2, <br />Firstly, I will gladly argue with you about steam locomotives until the cows come home. But please, don't go into personal attacks. We've had plenty of forum fires recently. <br /> <br />Firstly, cutoff does not effect maximum tractive effort, only average tractive effort throughout the stroke, and the horsepower consequently. Wether in full gear or hooked up, the valve gear will still admit full pressure to the cylinder, so in all cases the locomotive has full tractive effort at some portion of the piston's stroke (except of course when the reverser is very close to center and no steam is admitted). The Big Boy's engines' exact characteristics would of course vary depending on the time since last overhaul etc. In short, if you put the reverser full forward and open the throttle wide, you'll have full force throughout just about all of your motion (1.2 million pounds of inertia helps too). <br /> <br />I have to agree with the post above that the grade of coal also affected the Big Boy's horsepower. <br /> <br />And please, let's not get in a fight over a bunch of statistics where we're not even sure which numbers are right and which are wrong. <br /> <br />Sincerely, <br />Daniel Parks
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