What's so special about Big Boys?

[Anonymous]

I know that 8 Bigboys and I think 3 H8s survive, but as far as I know all the Y-6bs were scrapped. There were apparently 2 rusting in a scrap yard in Roanoke up until the seventies but I think that there gone now. (Can anybody shed any light on this)

There is a Y-6a (2156?) in a museum in Missouri but I don't know if there is much difference between the 2 sub classes.

[amtrakjackson]

Nothing. Real engines have extended range dynamic brakes.

[feltonhill]

Trainjunky29,

Your estimate of 75,000 lbs seems to be in the ballpark. I got 94,000 lbs train resistance at 1 mph for the 785-car train and about 71,000 lbs resistance for the 548-car train.

Actually, according to the info I have, a figure of 20 lbs/ton for starting inertia of friction bearings is at the low end of available estimates. Some sources go as high as 30-40 lbs/ton. The biggest problem is "bumping" each car into motion using slack. With a 100-150 car train, this isn't too bad; with 785 cars it's beyond careful. I was trying to illustrate that one BB could theoretically start and move such a train, and that it really wasn't such an over-the-top accomplishment. The downside was the practical matter of getting the whole assemblage moving without breaking in two.

GP40-2,

Yes, I've heard of cutoff. How else would the drawbar pull curves have been developed? Running a loco in full gear at speeds greater than 20-25 mph will exceed the boiler's capability to produce steam. From about 15 mph on, the loco is being hooked up. What are you driving at?

[Anonymous]

The Wyoming Division of the UP was and is a choke point for the railroad. Lines split off to the east and west but virtually everything goes through Wyoming. UP was a bridge route and traffic of all types went over the division in both directions. Sherman Hill on the east and the Wahsatch on the west are the major grades, but the saddle in the middle is roughly 350 miles with a 1% eastbound grade between Laramie and Sherman summit. Big Boys also worked the line down to Denver.

The Big Boys can be thought of as Challengers on steroids, their drivers were only 1 inch smaller. Like the Allegheny and the A, they were designed to start heavy trains AND to get them over the road at reasonable speeds without tying up this criitical bottleneck. They along with the Challengers pulled general freight, refer trains, livestock trains, and even troop trains. Coal drags were generally handled by older rebuilt 2-8-8-0's and during the war by a group of 30 2-8-8-2's purchased from the C&O and 5 2-8-8-2's from N&W. The N&W compounds tied up the Sherman hill so bad, they were re-assigned to the coal mine branch lines around Rock Springs, where they worked succesfully doing what they were designed to do for many years, outlasting the C&O locos.

Unlike the Allegheny's, Big Boys actually worked in the service they were designed for for many years and were doing so at the close of the steam era when Cheyene became almost a meca for steam fans. By then double headed Big Boys or occasionally a Big Boy double headed with a Gas Turbine thundering by was a memorable experience.

The name Big Boy came from a worker at Alco. The trade press caught on, and railroad PR departments of that time were always looking for something to hype as the biggest, greatest, fastest, etc, plus I suspect a lot of these claims are a little like fish stories. It's interesting to sepculate how many cars a Big Boy could drag out of a yard or what a NP Yellowstone would do burning eastern coal, but neither was really designed or optimized for that service. One reason steam loco's lasted as long as they did on certain roads, was because the railroads owned the coal mines.

[Modelcar]

Up829....An interesting bit of run down on what really took place.

[Anonymous]

Did a Big boy ever ride togethwe with a Big blow turbine?

I've seen a picture of it running with a "standard" turbine, but never with a big blow.

Accoarding to their years, it was possible, but doesn't mean they did it

[Anonymous]

One thing to bear in mind is that resistance from friction bearings decreases as speed increases. At low speed, you have brass (or bronze) on steel, but at higher speeds, a film of oil develops.

Sincerely,
Daniel Parks

[selector]

QUOTE: Originally posted by trainjunky29

One thing to bear in mind is that resistance from friction bearings decreases as speed increases. At low speed, you have brass (or bronze) on steel, but at higher speeds, a film of oil develops.

Sincerely,
Daniel Parks

You seem to support my assertion earlier, thanks. I hope someone will address my question...?

-Crandell

[GP40-2]

QUOTE: Originally posted by feltonhill

Trainjunky29,

Your estimate of 75,000 lbs seems to be in the ballpark. I got 94,000 lbs train resistance at 1 mph for the 785-car train and about 71,000 lbs resistance for the 548-car train.

Actually, according to the info I have, a figure of 20 lbs/ton for starting inertia of friction bearings is at the low end of available estimates. Some sources go as high as 30-40 lbs/ton. The biggest problem is "bumping" each car into motion using slack. With a 100-150 car train, this isn't too bad; with 785 cars it's beyond careful. I was trying to illustrate that one BB could theoretically start and move such a train, and that it really wasn't such an over-the-top accomplishment. The downside was the practical matter of getting the whole assemblage moving without breaking in two.

GP40-2,

Yes, I've heard of cutoff. How else would the drawbar pull curves have been developed? Running a loco in full gear at speeds greater than 20-25 mph will exceed the boiler's capability to produce steam. From about 15 mph on, the loco is being hooked up. What are you driving at?

Feltonhill,

What are you talking about????

I never mentioned you in that post. I was making a comment about the B.S. posts Electro-whatever and the Fantasy-junky29 made up.



Oldtimer,

No use arguing with the Trainjunky. He obviously know a lot more about steam locomotive than you will ever know[(-D] Besides, everybody just knows that the Big Boys were the greatest,most powerful, efficient,heaviest,longest,tallest,widest,highest tractive effort AND horsepower,best looking,best riding,best engineered,longest lasting (oh, wait a minute isn't that from a Chevy truck commercial??) locomotive.

[Anonymous]

Sayeth andysmith9670:

"There is a Y-6a (2156?) in a museum in Missouri but I don't know if there is much difference between the 2 sub classes."

There is no difference in the performance of the 4 2100-2200-series N&W 2-8-8-2s - the Y-5s, Y6s, Y6as and Y6bs. The Y6bs were the most famous because they were the newest, but as new improvements were developed the older 2100s were retrofitted with all of them.

Old Timer

[Anonymous]

Thanks for the info Old Timer.

[feltonhill]

GP40-2,

Misinterpreted your direction, my bad.

[Anonymous]

The name of the book that states that a Big Boy could haul a 5.5 mile train at 65 mph is Rails Across America. Though I concede that a Big Boy could not haul it at 65, I am confident that, with an experienced engineer, it could start it.

Dear GP40-2,
Please stop with the personal attacks.

Sincerely,
Daniel Parks

[feltonhill]

trainjunky29,

Thanks for the title. I'd forgot about the reference.

For those who don't have the book, it's an impressive looking thing, with various chapters written by well-known railroad history authors. The chapter you cited, Hard Times, was written by H. Roger Grant, author of several railroad history books outside Rails Across America. Currently Professor of History at Clemson, too. However, he makes one step into technical material and stubs his toe. Probably believed something he read along the way somewhere and didn't stop to check it out. I'm surprised that it got past the consulting editor, Bill Withuhn.

In a larger sense, how does one combat this sort of misinformation? Book looks good, prestigious writers, what chance do any of us lesser mortals have against that? Why, you can easily imagine people looking down their noses and saying, "How do you know more than he does? You're not an author!" Yep, he who publishes first wins.

Just one more example of how hype keeps going, and going, and going......

[timz]

What did he say, exactly?

After all, if you assemble it at Archer a 5 1/2 mile train will easily reach 65+ mph coasting downgrade eastward, if it holds together.

[feltonhill]

timz,

Good observation. The location wasn't specific either, so why not a downgrade?.

The author said:

"......Then the greatest steam beasts of all debuted in September 1941. Again, Union Pacific took the lead. Between 1941 and 1944 that company added 25 of the behemoth 4-8-8-4's called 'Big Boys,' to its fleet of locomotives. The only engines of their type, they weighed 600 tons and their 7,000 horsepower could pull a loaded 5 1/2 mile long train at speeds of 66 mph [not a typo] on level track."

Above quoted from Rails Across America, page 145, chapter titled Hard Times, by H. Roger Grant.

That's it. No relevant footnote or endnote that lists possible source that I can find.

[Anonymous]

QUOTE: Originally posted by feltonhill

trainjunky29,

Thanks for the title. I'd forgot about the reference.

For those who don't have the book, it's an impressive looking thing, with various chapters written by well-known railroad history authors. The chapter you cited, Hard Times, was written by H. Roger Grant, author of several railroad history books outside Rails Across America. Currently Professor of History at Clemson, too. However, he makes one step into technical material and stubs his toe. Probably believed something he read along the way somewhere and didn't stop to check it out. I'm surprised that it got past the consulting editor, Bill Withuhn.

In a larger sense, how does one combat this sort of misinformation? Book looks good, prestigious writers, what chance do any of us lesser mortals have against that? Why, you can easily imagine people looking down their noses and saying, "How do you know more than he does? You're not an author!" Yep, he who publishes first wins.

Just one more example of how hype keeps going, and going, and going......

The other thing is that steam locomotives could in reality do some incredible things--a class A hauling 160 cars on the level, an FEF-3 cruising at 100 just 10 miles out of a station stop, etc. It's hard to know where the capabilities end and the misinformation begins. When you see a book like Rails Across America, with the aforementioned prestigous and authoratative looks, you tend not to question it. Equations help, but they are not perfect, nor are the measurements of a locomotive's tractive effort, horsepower, etc. And just to make matters worse, there are so many numbers floating around for horsepower on big locomotives that agreeing on what is larger in one area is itself difficult.

Sincerely,
Daniel Parks

[GP40-2]

The Trainjunky said:

"The other thing is that steam locomotives could in reality do some incredible things--a class A hauling 160 cars on the level, an FEF-3 cruising at 100 just 10 miles out of a station stop, etc."

Really, you think that is incredible?

The Class A was a fine locomotive, but a single AC4400 would have no trouble pulling twice that amount of cars on level track.

A GE P42 can be crusing at 110mph in 2 minutes from a station stop not alone 10 miles.

The REALITY is that even really good steam locomotives such as the Class A and FEF-3 couldn't compete with first generation diesel-electrics in the 1950's, not alone with what we have today.

Of course, I fully expect you to "respectfully disagree" with the above statement.

[feltonhill]

GP40-2,

I'm sure you know (and most everyone else here as well), that an N&W Class A could pull 160 cars between Williamson and Portsmouth, but on a very slight downgrade with many curves. They also could make at least 40-45 mph with this load. After the addition of a-tanks, they did the route non-stop with as many as 180 cars in about 3.5 to 4 hours. Every day, nothing special.

OK, a single AC4400 could start considerably more than 160 cars, maybe as many as 320 as you claim. However, it couldn't make 40 mph with that load. I doubt that a single AC4400 could make 40-45 mph with 160 cars over that line.

Trainjunky29's estimate of an FEF3 being able to make 100 mph in 10 miles is possible, but I doubt it would be more than an 800-900 ton train (about 12-13 cars). The AAR tests in 1938 set a goal of getting a 1000-ton 15-car train to 100 mph and an FEF-1 managed 102 mph on a slight downgrade (about -0.15% IIRC), not on level track. But how many cars could a single P42 get to 110 mph in 2 minutes? 12-13 sounds unlikely.

It would further everyone's knowledge of trains if you would provide some additional context with your examples.

[Anonymous]

QUOTE: Originally posted by GP40-2


Of course, I fully expect you to "respectfully disagree" with the above statement.

Wow, you're good! [:)][:D][8D]

[timz]

QUOTE: Originally posted by GP40-2

A GE P42 can be crusing at 110mph in 2 minutes from a station stop not alone 10 miles.

Sounds crazy, but read it again-- he said a P42, not a P42 pulling a train. So he might be right.

[tree68]

I recall reading some time ago that steam engines came into their own at higher speeds, and that if it weren't for the physical problems of wheel balance and steam production, they would have no practical top end. It frankly surprises me that an FEF would take 10 miles to get to 110mph - I'd expect it sooner, but that's just my impression.

It doesn't take much to humble a locomotive, though. The brief time I ran an old ALCo C424 included a period in notch 8, with just 4 passenger cars on the drawbar, on a 2% upgrade. I was just holding track speed at 25 mph with the throttle full open...

There are a number of steam locomotives that were purpose-built. My favorite, the Berkshire, was designed to haul freight at high speeds, which is exactly what it did, especially for the NKP. Other locomotives may have been bigger and/or faster, but a little marketing made the Big Boy the giant that many perceive it to have been...

[Modelcar]

....The fact the name "Big Boy"...introduced by an employee may have contributed too.

[timz]

QUOTE: Originally posted by tree68

I recall reading some time ago that steam engines came into their own at higher speeds, and that if it weren't for the physical problems of wheel balance and steam production, they would have no practical top end. It frankly surprises me that an FEF would take 10 miles to get to 110mph - I'd expect it sooner, but that's just my impression.

When an 80-inch-driver engine is running 110 mph, each piston stroke takes 0.065 seconds, and the valve is open for maybe a third of that time. So the steam has maybe 1/40 of a second to get into the cylinder. It's a mystery that a steam locomotive can pull at all at that speed. The notion that steam has some sort of high-speed advantage is mostly wishful thinking; remember R. P. Johnson gave us an example of it in his book, in the chapter on high speed trains?

[Anonymous]

Just to clarify, I was talking about an FEF-3 with a respectable passenger train in tow.

[Anonymous]

QUOTE: Originally posted by timz

QUOTE: Originally posted by tree68

I recall reading some time ago that steam engines came into their own at higher speeds, and that if it weren't for the physical problems of wheel balance and steam production, they would have no practical top end. It frankly surprises me that an FEF would take 10 miles to get to 110mph - I'd expect it sooner, but that's just my impression.

When an 80-inch-driver engine is running 110 mph, each piston stroke takes 0.065 seconds, and the valve is open for maybe a third of that time. So the steam has maybe 1/40 of a second to get into the cylinder. It's a mystery that a steam locomotive can pull at all at that speed. The notion that steam has some sort of high-speed advantage is mostly wishful thinking; remember R. P. Johnson gave us an example of it in his book, in the chapter on high speed trains?

Yes, but the steam's under a lot of pressure.

Let's not get into a steam vs. diesel debate--we'll never get out of it.[:)][:D][8D]

[GP40-2]

QUOTE: Originally posted by feltonhill

GP40-2,

I'm sure you know (and most everyone else here as well), that an N&W Class A could pull 160 cars between Williamson and Portsmouth, but on a very slight downgrade with many curves. They also could make at least 40-45 mph with this load. After the addition of a-tanks, they did the route non-stop with as many as 180 cars in about 3.5 to 4 hours. Every day, nothing special.

OK, a single AC4400 could start considerably more than 160 cars, maybe as many as 320 as you claim. However, it couldn't make 40 mph with that load. I doubt that a single AC4400 could make 40-45 mph with 160 cars over that line.

Trainjunky29's estimate of an FEF3 being able to make 100 mph in 10 miles is possible, but I doubt it would be more than an 800-900 ton train (about 12-13 cars). The AAR tests in 1938 set a goal of getting a 1000-ton 15-car train to 100 mph and an FEF-1 managed 102 mph on a slight downgrade (about -0.15% IIRC), not on level track. But how many cars could a single P42 get to 110 mph in 2 minutes? 12-13 sounds unlikely.

It would further everyone's knowledge of trains if you would provide some additional context with your examples.

Feltonhill,

First, some questions for you questions, then some test data for you to play with:

What exactly do you mean about "a very slight downgrade" How much in grade percent are we talking about for the gravity assistance for the Class A?

What was the tonnage of the N&W trains? 160 cars is somewhat meaningless if we are compairing WW2 era coal cars vs 130 ton modern coal cars.

Some test data for context:

CSX CW44AC #523 recorded 180,000 lbs continious pull @ 8.5 MPH and 32,288 lbs. continious pull at 50 MPH when tested in 2002

CSX CW60AC #602 recorded 44,212 lbs continious pull @ 50 MPH when tested in 2000

GE tests of P42's (no locomotive # specified in my copy of the tests) showed 14,438 lbs pull at 100 MPH. What was the pull of the FEF's at 100 MPH?

I am not familar with the routes in your examples, so you can plug the above numbers in and report the results.

[GP40-2]

QUOTE: Originally posted by trainjunky29

QUOTE: Originally posted by timz

QUOTE: Originally posted by tree68

I recall reading some time ago that steam engines came into their own at higher speeds, and that if it weren't for the physical problems of wheel balance and steam production, they would have no practical top end. It frankly surprises me that an FEF would take 10 miles to get to 110mph - I'd expect it sooner, but that's just my impression.

When an 80-inch-driver engine is running 110 mph, each piston stroke takes 0.065 seconds, and the valve is open for maybe a third of that time. So the steam has maybe 1/40 of a second to get into the cylinder. It's a mystery that a steam locomotive can pull at all at that speed. The notion that steam has some sort of high-speed advantage is mostly wishful thinking; remember R. P. Johnson gave us an example of it in his book, in the chapter on high speed trains?

Yes, but the steam's under a lot of pressure.

Let's not get into a steam vs. diesel debate--we'll never get out of it.[:)][:D][8D]

Yes, but pressure and volume are inversely proportional, so with the limited time available for steam to enter the cylinder at high speed, along with the high pressure, not much volume of steam gets into the cylinder, does it? Darn, another one of you fantasies shot down by physics....

[GP40-2]

QUOTE: Originally posted by tree68

I recall reading some time ago that steam engines came into their own at higher speeds, and that if it weren't for the physical problems of wheel balance and steam production, they would have no practical top end. It frankly surprises me that an FEF would take 10 miles to get to 110mph - I'd expect it sooner, but that's just my impression.

As timz said, whishful thinking.

From an eariler Feltonhill post:

Speed - Calc TE (lbs) - Actual DB Pull (lbs) - Actual DBHP

0 - 135,300 - 131,000 - 0
10 - 132,500 - 124,000 - 3,307
20 - 109,000 - 98,000 - 5,227
30 - 83,000 - 75,000 - 6,000
40 - 67,000 - 57,000 - 6,080
50 - 56,100 - 43,000 - 5,733
60 - 48,700 - 32,000 - 5,120

You can see power is decreasing as speed increases, largely as a result of the greater cutoff needed to accelerate the locomotive. A steam locomotive's power curve is exponential in nature, and you would see even more dramatic power loss from 60 to 70 mph and from 70 to 80 mph.

[Anonymous]

True, but it's the pressure that causes the force on the piston, not the volume. The volume comes into play when trying to conserve steam--take away to much steam and the boiler pressure goes down.

Sincerely,
Daniel Parks