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What a Challenger could really do...

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Posted by santafe5011 on Friday, May 26, 2017 7:10 AM

HI i´m spanish and i have an vhs were you can see 3985 going full speed with that consist, i find the video on youtube so here it is https://www.youtube.com/watch?v=r_yHO0fZDaQ 

it starts at 22:30, it must have much more than 4700 dbh that people is saying, it´s going at least 65 mph if no more with a near 8000 ton train.

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Posted by timz on Tuesday, May 4, 2010 6:14 PM

GP40-2
timz

On level track, you mean? No reason to assume the IC 4-8-2 was on the level.

Well, I guess it could be going downhill and getting a 6500 HP assist from gravity. Are the hills that big in that area?

We can't rule out 0.4% down, which would supply that.
GP40-2
Once you have that data on the locomotive and train forces, this is a very straight forward physics problem to repeatedly model.
Correct-- once we have done the tests needed to find out how much power it takes to pull the train, then we know how much power it takes to pull the train. Until then, physics doesn't help (on level track).

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Posted by CSSHEGEWISCH on Tuesday, May 4, 2010 10:18 AM

Yardmaster01

OK, so it only took the locomoive builders 50+ yrs. to come up with a DE that can equal "modern" steam on a unit for unit basis, I can live with that.  Now for a couple of other monkey wrenches, Dante Porta and ACE 3000.  What if? 

Although it took while to get 4000+ HP in a single unit, multiple unit control renders that argument moot, ATSF was running 4-unit 5400 HP FT sets across the Arizona desert (without water stops) in 1944.  ACE 3000 is dormant, if not dead.  Dante Porta's designs may be in the same situation.  After all, Manchuria is the N&W of worldwide steam locomotion, which also means that the end is near for steam locomotives in regular service.

The daily commute is part of everyday life but I get two rides a day out of it. Paul
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Posted by Grantham on Tuesday, May 4, 2010 8:08 AM

Even if we discount the size of the hills over the section of line that the train covers, it remains a very impressive train, hauled by a very impressive loco. It's great to see the lack of diesel assistance which indicates that the railway company either wants to prove the loco or at the very least, trusts it.

 

Great video!

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Posted by GP40-2 on Monday, May 3, 2010 10:37 PM
timz

On level track, you mean? No reason to assume the IC 4-8-2 was on the level.

Well, I guess it could be going downhill and getting a 6500 HP assist from gravity. Are the hills that big in that area?

timz

But "physics" doesn't tell us anything specific about how much power is needed on the level. We need tests for that.

I'm assuming by "tests", you mean data collection for the computations? Once you have that data on the locomotive and train forces, this is a very straight forward physics problem to repeatedly model.

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Posted by selector on Monday, May 3, 2010 7:40 PM

Yardmaster01
OK, so it only took the locomoive builders 50+ yrs. to come up with a DE that can equal "modern" steam on a unit for unit basis...

Not to quibble, but it took them over 100 years in steam development to get to where they were at the point of the Challenger.  Diesels have been under development for about 70-ish.  We'll have to wait for three decades to see where the diesel crowd finds itself after the equivalent passage of time. Big Smile

-Crandell

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Posted by Yardmaster01 on Monday, May 3, 2010 6:18 PM

OK, so it only took the locomoive builders 50+ yrs. to come up with a DE that can equal "modern" steam on a unit for unit basis, I can live with that.  Now for a couple of other monkey wrenches, Dante Porta and ACE 3000.  What if? 

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Posted by timz on Monday, May 3, 2010 2:23 PM

GP40-2
It just says a specific amount of power is needed to move a certain amount of mass at a specific speed.

On level track, you mean? No reason to assume the IC 4-8-2 was on the level.

But "physics" doesn't tell us anything specific about how much power is needed on the level. We need tests for that.

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Posted by Anonymous on Monday, May 3, 2010 1:52 PM

Some additional infos about that 3985-APL run in '91:

Hope not repeating something, but in fact the run was,
with the one notable exception at Archer Hill, a downhill run.

The average speed of that train was in the upper forties.

Just look at the elevation at Cheyenne and North Platte. I think the constant loss over that distance is -0.25%.
I believe Tim has the most detailed plans about the track condition.

Another fact, does not have those multi-linked double-stack trains some general advantage in rolling resistance?
If not, why there were built like that... OK, some others, too, train length, less dead weight, etc.

Consider also that the engine was totally overhauled at that time,
burning oil and others advantages... I think all that helped to do the trick,
regardless it produced 4700 or 5000  DBHP. Delta is less than 10%,
that a fine estimation in my eyes.

Let a train like that running through sags,  
we might have even accelerated to nearly 70mph, for a short time.

A Challenger would not be good to pull constantly 7000 tons at a grade of 0.7%. The grade of 0.82%, was the most commonly used grade between Wahsatch and Cheyenne. A Chally was rated
4290tons, 1948- era friction wheels, considering an av. speed of 15-20mph.

There were 3 GE-Dash's, I think that is correct, that pulled the train into Cheyenne, than Chally took over it.
The Train it took back to Cheyenne, now running constly. 0.25% up, was much smaller, 1000tons, or so.

http://www.youtube.com/watch?v=GyZD7fJ12WI&feature=related


If anybody would like to have a sequence of the tape for more infos, post me, I digitized it.

What I want to say, seen from a overall performance, it is pretty that of an AC4400.

If you really want a mess, look at this...

http://www.youtube.com/watch?v=aoGBL0XFjQ8

 

Cheers

lars

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Posted by GP40-2 on Sunday, May 2, 2010 7:09 PM
oltmannd
CAZEPHYR
The picture below pacing the 2502 at up to 77 mph with a sixty five car banana train in 1954 shows steam at what it does best.  We paced this train for thirty miles or so north on Illinois 45 and watched as that locomotive just ate up the miles at speed.  I don't believe any single diesel today could have done the same speed as this locomotive could do.    
You are right. A single diesel locomotive cannot haul a 65 car, 3250 ton train a 77 mph on the level. It takes 10,000 HP to do that. 6000 HP would get you to 60 mph on the level. An AC6000 can do that.

HP is HP, steam or diesel doesn't matter. I don't know of any steam locomotive boilers rated at 10,000 HP, either.

Good point on the total power required to move X amount of mass at Y mph. This is simple question of physics. Either that train was totally empty, or it wasn't 65 cars, or it wasn't traveling anywhere near 77 mph. That's the mathematical beauty of physics, it doesn't care whether the locomotive is steam or diesel like a railfan might. It just says a specific amount of power is needed to move a certain amount of mass at a specific speed. There is no way of getting around that.
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Posted by BigJim on Sunday, May 2, 2010 10:01 AM

You are right. A single diesel locomotive cannot haul a 65 car, 3250 ton train a 77 mph on the level.

Initially we we talking about something 18 - 22 cars in the 1500 - 1800 ton range. Although it is a safe bet it will never happen, there is a very real possibility that a drag race between UP's finest AC44 and 3985 could take place. I have no idea, but, does not UP have some 79mph track to run on?

What is needed here is some input from a UP engineer who has run the big AC units and knows how they perform.

.

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Posted by CAZEPHYR on Sunday, May 2, 2010 8:17 AM

Redwards

CZ,

 I love that banana train pacing shot - thanks for posting.  It reminded me of the signature picture from 'The Mohawk that Refused to Abdicate' where the Mohawk in question blasts past Morgan and Hastings.

--Reed

Reed

Thanks.  We got to see that train many times but only paced it one time at speeds like this.  

I have that book also by Morgan and Hastings and that story was repeated many times by different railroads in the early fifites.

CZ

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Posted by Redwards on Sunday, May 2, 2010 8:04 AM

CZ,

 I love that banana train pacing shot - thanks for posting.  It reminded me of the signature picture from 'The Mohawk that Refused to Abdicate' where the Mohawk in question blasts past Morgan and Hastings.

--Reed
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Posted by oltmannd on Saturday, May 1, 2010 11:06 AM
CAZEPHYR
The picture below pacing the 2502 at up to 77 mph with a sixty five car banana train in 1954 shows steam at what it does best.  We paced this train for thirty miles or so north on Illinois 45 and watched as that locomotive just ate up the miles at speed.  I don't believe any single diesel today could have done the same speed as this locomotive could do.    
You are right. A single diesel locomotive cannot haul a 65 car, 3250 ton train a 77 mph on the level. It takes 10,000 HP to do that. 6000 HP would get you to 60 mph on the level. An AC6000 can do that.

HP is HP, steam or diesel doesn't matter. I don't know of any steam locomotive boilers rated at 10,000 HP, either.

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by CAZEPHYR on Saturday, May 1, 2010 10:05 AM

GP40-2
CAZEPHYR

The picture below pacing the 2502 at up to 77 mph with a sixty five car banana train in 1954 shows steam at what it does best.  We paced this train for thirty miles or so north on Illinois 45 and watched as that locomotive just ate up the miles at speed.  I don't believe any single diesel today could have done the same speed as this locomotive could do.    

Before you can make a statement like that, we would have to know what was the tonnage of the train, what was the gradient in that area, and what exactly is that locomotive in the picture. Without that information, comparisons to other locomotives, whether steam, diesel, or electrics are meaningless.

You are correct about this conversation being meaningless.  We are discussing something that can never take place and to continue making a comparison is not productive.  Sorry I gave you an example of steam in action.  

CZ

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Posted by GP40-2 on Friday, April 30, 2010 11:43 PM
CAZEPHYR

The picture below pacing the 2502 at up to 77 mph with a sixty five car banana train in 1954 shows steam at what it does best.  We paced this train for thirty miles or so north on Illinois 45 and watched as that locomotive just ate up the miles at speed.  I don't believe any single diesel today could have done the same speed as this locomotive could do.    

Before you can make a statement like that, we would have to know what was the tonnage of the train, what was the gradient in that area, and what exactly is that locomotive in the picture. Without that information, comparisons to other locomotives, whether steam, diesel, or electrics are meaningless.

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Posted by GP40-2 on Friday, April 30, 2010 11:33 PM
CAZEPHYR

...The limit on the diesel speed is the gearing, not the software...

You are still stuck in the DC traction motor era mindset on this. CSX's AC6000s are software limited to 75 MPH. With their current gearing, they would have to hit 110-115 mph before the AC motors are in any danger of over speeding. Whether or not you would want a locomotive with CSX's axle loading hitting 100+ is another story.

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Posted by CAZEPHYR on Friday, April 30, 2010 11:21 PM

GP40-2
CAZEPHYR

timz

BigJim
Can I use an SD40-2?

If you do, don't bet on yourself.

With 15 cars 1005 tons, the 4-8-4 allegedly reached 75 in 5.02 minutes, 19400 ft. If the single-unit diesels can win any race, that's the one to try for, since the 4-8-4's weight disadvantage has the greatest effect.

Knowing the parameters of the bet is limited to the gearing speed of the diesel, change the top speed to at least 90 mph and see which engine will win.  After all, we are talking about a 1946 steam locomotive that was designed and put into service sixty four years ago and was designed to run at 90 mph or more on a passenger train against a 2009 freight locomotive that is geared for 75 mph.  They also were used in freight and did well in that asignment even with the 79" drivers. 

This one is a sure bet for the 4-8-4.

  Hardly a good comparison.   

CZ

I'll bet on the 4-8-4 too vs. a single AC44. On the other hand, a CSX AC6000, with the software enabled to let it run at 90-100 mph, would eat the Niagara for a lunch with that train.

 

The limit on the diesel speed is the gearing, not the software.   It would be an interesting match up for sure, but my money would still be on the 4-8-4.   

CZ

The picture below pacing the 2502 at up to 77 mph with a sixty five car banana train in 1954 shows steam at what it does best.  We paced this train for thirty miles or so north on Illinois 45 and watched as that locomotive just ate up the miles at speed.  I don't believe any single diesel today could have done the same speed as this locomotive could do.    

 

CZ

 

 

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Posted by BNSFwatcher on Friday, April 30, 2010 9:19 PM

Did someone say "lunch"?  On the NYC?  I'll have the Welch rarebit, with bacon rashers and sliced tomatoes, and a bottle of Genesee beer, please.  Yes, I wrote it down....  Thank you!

Hays

 

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Posted by selector on Friday, April 30, 2010 7:14 PM

Hang on, guys...I have the Broadway Limited Imports versions of each of those in HO scale.  I'll test them and get right back.  How about best out of three trials?

Laugh

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Posted by GP40-2 on Friday, April 30, 2010 6:46 PM
CAZEPHYR

timz

BigJim
Can I use an SD40-2?

If you do, don't bet on yourself.

With 15 cars 1005 tons, the 4-8-4 allegedly reached 75 in 5.02 minutes, 19400 ft. If the single-unit diesels can win any race, that's the one to try for, since the 4-8-4's weight disadvantage has the greatest effect.

Knowing the parameters of the bet is limited to the gearing speed of the diesel, change the top speed to at least 90 mph and see which engine will win.  After all, we are talking about a 1946 steam locomotive that was designed and put into service sixty four years ago and was designed to run at 90 mph or more on a passenger train against a 2009 freight locomotive that is geared for 75 mph.  They also were used in freight and did well in that asignment even with the 79" drivers. 

This one is a sure bet for the 4-8-4.

  Hardly a good comparison.   

CZ

I'll bet on the 4-8-4 too vs. a single AC44. On the other hand, a CSX AC6000, with the software enabled to let it run at 90-100 mph, would eat the Niagara for a lunch with that train.
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Posted by CAZEPHYR on Friday, April 30, 2010 6:06 PM

timz

BigJim
Can I use an SD40-2?

If you do, don't bet on yourself.

With 15 cars 1005 tons, the 4-8-4 allegedly reached 75 in 5.02 minutes, 19400 ft. If the single-unit diesels can win any race, that's the one to try for, since the 4-8-4's weight disadvantage has the greatest effect.

Knowing the parameters of the bet is limited to the gearing speed of the diesel, change the top speed to at least 90 mph and see which engine will win.  After all, we are talking about a 1946 steam locomotive that was designed and put into service sixty four years ago and was designed to run at 90 mph or more on a passenger train against a 2009 freight locomotive that is geared for 75 mph.  They also were used in freight and did well in that asignment even with the 79" drivers. 

This one is a sure bet for the 4-8-4.

  Hardly a good comparison.   

CZ

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Posted by timz on Friday, April 30, 2010 1:05 PM

BigJim
Can I use an SD40-2?

If you do, don't bet on yourself.

With 15 cars 1005 tons, the 4-8-4 allegedly reached 75 in 5.02 minutes, 19400 ft. If the single-unit diesels can win any race, that's the one to try for, since the 4-8-4's weight disadvantage has the greatest effect.

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Posted by timz on Friday, April 30, 2010 1:03 PM

blue streak 1
This statement leaves many questions unanswered.

True.

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Posted by BigJim on Thursday, April 29, 2010 8:16 PM

"0 to 75 mph in 9.00 minutes and 37200 ft (averaging less than 0.03% downgrade). "

Gee whiz! That's seven miles!
Welp, I'll double my bet on the diesel.
Can I use an SD40-2? Can I? Can I?

.

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Posted by blue streak 1 on Thursday, April 29, 2010 7:18 PM

timz
NY Central did do actual tests too, and the time their 4-8-4 took to accelerate 22-car trains to 75 mph will be hard for an AC44  to match 

timz:This statement leaves many questions unanswered.

1. What year was the test conducted?

2. Were the cars three axel or 2 axel trucks? 3  axels track and ride better.

3. Did the cars have axel generators?

a.. Were the generators belt driven or geared?

4. Was it summer and was the A/C  running and what kind of A/C? electromechanical or some other kind that did not drag the train? 

5. Friction bearings or roller bearings or a mix?

6. Tight lock couplers or type "E"?

7. Streamlining or connventional cars?

8. Car profiles all the same?

9. Other factors that someone may think of.?

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Posted by timz on Thursday, April 29, 2010 5:13 PM

BigJim
timz

Close to a match, against most steam in most situations. NY Central did do actual tests too, and the time their 4-8-4 took to accelerate 22-car trains to 75 mph will be hard for an AC44 to match.

What kind of tonnage did those 22 cars weigh?

They were coaches-- without checking the report I'll guess it said 1520 tons. I do remember the figures for the 27-car train: 1875 tons, 0 to 75 mph in 9.00 minutes and 37200 ft (averaging less than 0.03% downgrade). It's questionable whether they had really reached 75-- might have been only 73 or 74-- but covering that distance in that time from a standing start is impressive in itself.

Offhand I'm guessing the 4-8-4 would have more of an advantage in the 25-70 race than in the 0-70. It's more powerful over most of that range-- but then it has to be, to make up for its extra 250? tons.

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Posted by selector on Thursday, April 29, 2010 2:07 PM

Yes, that is a good question.  A heavyweight coach with A/C would be in the order of 147K lbs, so 22 of them would come to about 1,600 tons, plus or minus for the different cars comprising a train.  I would think an AC44 would be able to start that tonnage with ease, and it would surely out-pull a Niagara until perhaps 25 mph.

-Crandell

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Posted by BigJim on Thursday, April 29, 2010 1:17 PM

timz

Close to a match, against most steam in most situations. NY Central did do actual tests too, and the time their 4-8-4 took to accelerate 22-car trains to 75 mph will be hard for an AC44 to match.


What kind of tonnage did those 22 cars weigh?

From a standing start, I would put my money on the AC44. If they were to start a race where they were drifting at say 25mph, then I might go for the steamer. It would be a half mile down the road before that GE started to load up.

 

.

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