USA Pics
- Thread starter Dermmy
- Start date
SouthwestinAZ1
BNSF Peavine Foamer
Almost looks like a NJT train is on the wrong side of the country, shot looks like one of the crossings in San Clemente, CA.
64Warhorse
New member
Lordy, Josh --- 26,000 hp on the head end? I can hear the couplers popping from, here ...
Lordy, Josh --- 26,000 hp on the head end? I can hear the couplers popping from, here ...
Nope! There is a limit to the number of powered axles at the head end and most of those units have non-conventional axles which count as 1.5 axles each. The exact calculation varies a bit from railroad to railroad, but almost anywhere that consist would work out at about three units under power, maybe four. The rest are dead in train or at most idling and pumping air. The couplers are safe!
Damn shame though that you can't replicate that sort of thing in Trainz. Trees that sway in the breeze add so much more.....
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norfolksouthern37
what's a normal map?
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Thanks Scott.
It's JR's standard 20800 tank cars, and even though they have a slightly reflective surface, it is the "chrome" texture in this case that shines the most, hehe.
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It is the same cars as the those "chromed" (JR's 20800 tank cars) that I have reskinned.
// Erik from Sweden
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Lordy, Josh --- 26,000 hp on the head end? I can hear the couplers popping from, here ...
hahahaha well with a 19,000 ton mixed freight and a 3% grade you need a TON of power. There are also 2 Dash-9's on the rear end for helpers
Blutorse4792
Now T:ANE I can get into
The mid-day Varsity switches onto the Janesville Subdivision, en route to Madison, WI.
Off Topic
Just out of curiosity (and to earn my 'Nutty Professor' tag) I ran the numbers:
Now there are different formulas and higher adhesion is claimed for some modern locos, but this is pretty realistic:
Drawbar pull is 20lb/ton/percent of grade = 20 * 19000 * 3 = 1.14 million pounds. Now assuming something hasn't broken already....
At 30% adhesion (typical, but then 'typical' isn't a 3% grade, so call this optimistic!) 1.14 mil pounds of drawbar pull requires about 3.8 million pounds on the loco axles just to hold the load. That equals 1,900 tons, say 200 tons per loco and you need 10 locos (cause you can't have 9.5!) just to not be sliding backwards. Sorry, but even with the units on the rear it's time to dump the train air, cross your fingers and jump...
Just out of curiosity (and to earn my 'Nutty Professor' tag) I ran the numbers:
Now there are different formulas and higher adhesion is claimed for some modern locos, but this is pretty realistic:
Drawbar pull is 20lb/ton/percent of grade = 20 * 19000 * 3 = 1.14 million pounds. Now assuming something hasn't broken already....
At 30% adhesion (typical, but then 'typical' isn't a 3% grade, so call this optimistic!) 1.14 mil pounds of drawbar pull requires about 3.8 million pounds on the loco axles just to hold the load. That equals 1,900 tons, say 200 tons per loco and you need 10 locos (cause you can't have 9.5!) just to not be sliding backwards. Sorry, but even with the units on the rear it's time to dump the train air, cross your fingers and jump...
That equation is spot on.. However, the adhesion factor achieved by today's modern GEVO's and ACe's is actually only about 20-25% range though they claim to reach 30% adhesion factor. The equation above gives you what kind of tractive effort is needed to move a train. Beware, for example, locomotives like ES44AH weigh 432,000 lbs and are capable of making the maxium 33,000 lbs of tractive effort. If trainz is realistic and I run the numbers for that, the 19,000 ton freight which is equal to 1.14 million pounds of drawbar pull requiring 3.8 million pounds of power.. the equation shown in the quote holds true. What changes is the number of tons per locomotive using ES44AH, instead of 200 tons per locomotive, we have 216 tons per locomotive. with the 1900 tons required to keep the train from rolling backwards down the grade, you divide the 1900 tons by the 216 tons and your end result should be 8.79 (9) locomotives. Thus that is 1 less locomotive needed than the standard 10 it would usually take..Just out of curiosity (and to earn my 'Nutty Professor' tag) I ran the numbers:
Now there are different formulas and higher adhesion is claimed for some modern locos, but this is pretty realistic:
Drawbar pull is 20lb/ton/percent of grade = 20 * 19000 * 3 = 1.14 million pounds. Now assuming something hasn't broken already....
At 30% adhesion (typical, but then 'typical' isn't a 3% grade, so call this optimistic!) 1.14 mil pounds of drawbar pull requires about 3.8 million pounds on the loco axles just to hold the load. That equals 1,900 tons, say 200 tons per loco and you need 10 locos (cause you can't have 9.5!) just to not be sliding backwards. Sorry, but even with the units on the rear it's time to dump the train air, cross your fingers and jump...
slave-driver
Sacramento Nothern Lives
Just out of curiosity (and to earn my 'Nutty Professor' tag) I ran the numbers:
Now there are different formulas and higher adhesion is claimed for some modern locos, but this is pretty realistic:
Drawbar pull is 20lb/ton/percent of grade = 20 * 19000 * 3 = 1.14 million pounds. Now assuming something hasn't broken already....
At 30% adhesion (typical, but then 'typical' isn't a 3% grade, so call this optimistic!) 1.14 mil pounds of drawbar pull requires about 3.8 million pounds on the loco axles just to hold the load. That equals 1,900 tons, say 200 tons per loco and you need 10 locos (cause you can't have 9.5!) just to not be sliding backwards. Sorry, but even with the units on the rear it's time to dump the train air, cross your fingers and jump...
Your both right but your both wrong. The older locomotives like the ones in the screenie, (SD7's, 9's, 40-2's) that brought this discussion on were the ones that had from 20 to 25% tractive effort per pound of locomotive weight. The newer locos like the ES44AC's, SD70Ace's, (AC traction locos) and such are the ones with the 30 to 34% tractive effort per pound of locomotive weight. The modern DC traction locos are still getting around 25%.
Bill
Still off topic....
Hi Bill - long time
You're right, but you're wrong! The post that brought the discussion on was jmano33's post at #23468 which shows a lash up of 5 Gevos plus an SD70 (or 80, I can never remember which is which LOL) which led to the 26k HP quip, which led to the 19000 tons on 3% reply which set me to thinking....
Thinking some more, theoretical adhesion is quoted on perfect wheels and perfect rail and dead level - on 3% in working conditions it's gonna be a good bit less. Then to that 19k tons you have to add the weight of the 10 locos, so you probably need to add yet another loco to counter the backward slide of the 10 (or 9!) you've already got. It's gettin' silly LOL. There's a busted knuckle in there somewhere.....
Hi Bill - long time
You're right, but you're wrong! The post that brought the discussion on was jmano33's post at #23468 which shows a lash up of 5 Gevos plus an SD70 (or 80, I can never remember which is which LOL) which led to the 26k HP quip, which led to the 19000 tons on 3% reply which set me to thinking....
Thinking some more, theoretical adhesion is quoted on perfect wheels and perfect rail and dead level - on 3% in working conditions it's gonna be a good bit less. Then to that 19k tons you have to add the weight of the 10 locos, so you probably need to add yet another loco to counter the backward slide of the 10 (or 9!) you've already got. It's gettin' silly LOL. There's a busted knuckle in there somewhere.....
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slave-driver
Sacramento Nothern Lives
It has been a wile Andy.:wave:
Nothing like the smell of being corrected in the morning. I was thinking it was in reference to a different post. However look carefully at what motive power in the post in which you referred. I'm only seeing 1 Gevo and 1 SD70ACe. The rest are -9's. All DC traction at 25 to 28% tractive effort. Game match and set. :hehe:
Bill
Nothing like the smell of being corrected in the morning. I was thinking it was in reference to a different post. However look carefully at what motive power in the post in which you referred. I'm only seeing 1 Gevo and 1 SD70ACe. The rest are -9's. All DC traction at 25 to 28% tractive effort. Game match and set. :hehe:
Bill
Sniff! I forgot that factor! We now see why the AC Traction motor still has a major advantage over the standard DC traction motor...
Andy,
I got the message from Auran telling me my PM box was full. I have since cleaned it out. So feel free to write me again.. Good to see that other people are interested in the science of how locomotives work!
