Steam & Excursion > Bigger then Big Boy

Did any other railroads have anything planned that would have been bigger then a Big Boy?

If "bigger" means "heavier engine-only weight"
then the heavier 2-6+6-6s are said to be.
If "bigger" means "longer over engine and tender"
then the 6-4-4-6 wins.

the UP big boy only won 1st place in 2 categories, total engine weight and total engine and tender weights.  every other category was topped out by another articulated engine.  dave, out.

http://steamlocomotive.com/locobase.php?country=USA&wheel=2-8-8-4



Edited 1 time(s). Last edit at 01/08/19 10:50 by davebb71.

Offhand guess: no articulated was longer than Big Boy.

timz Wrote:
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> Offhand guess: no articulated was longer than Big
> Boy.

Without actually looking up the dimensions, what about the DM&IR Yellowstones and the SP AC-9 Yellowstones?

While its obvious that the Big Boys were in fact not the most powerful, nor the "most" in a number of other categories they, (for a variety of reasons) have been crowned that by the media for decades and that's a fact.

   So let's enjoy the fact that when Ed Dickens and his merry band of warriors bring the 4014 back to life she will in fact be the "most" in every category amongst that small breed of American mainline steam locomotives given a second life.

   IMHO-Ross Rowland  

How big are the 4-8-4+4-8-4 Bayer-Garrett's?

HotWater Wrote:
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> Without actually looking up the dimensions, what
> about the DM&IR Yellowstones and the SP AC-9
> Yellowstones?
UP 4000 is 132' 9 1/2"
DMIR M4 is 127' 11"
SP AC-11 is 123' 8 3/8"

-John

The Norfolk & Western had a very large single expansion 2-8-8-2 on the drawing board that they were going to call the Y-7.  Here are some of the design parameters:

The proposed Y7 would have 26x30  cylinders, 63"drivers, tractive effort of 153,000 pounds, and 130 sq feet of grate area. 112" max outside dia boiler. Boiler pressure was going to be 300 psi.  Pumps would be mounted on smokebox and 122 ft long with N&W streamlined tender.  

Not quite as long as a Big Boy, but probably would have been heavier with that huge boiler and large steam chest.

If I remember correctly, the next issue of Classic Trains is going to have an article about larger Big Boys the UP was considering but never ordered.  By the early 1940's, most railroads recognized that the diesel was the future. 

 

PRR’s Q2, 4-6-4-4 developed 8,000 HP..at speed...

Big Boy was NOT the greatest HP locomotive ...being able to exert the strongest pull at the highest speeds....

As I’ve said , fire intensity is dependent upon the strength of the draft up the stack —— which is determined by the load behind the tender’s coupler.  

Even with diesels in full dynamic brakes, the retarding capacity ( HP ) of the dynamics drops off severely, as track speed increases.
if not careful, or if carefully managed , the BIG BOY could drag multiple diesels at full capacity braking HP , at speeds at which the current limiting circuitry ( reduced field excitation) could give the 4014 tha capabikity to drag the dismals faster than their dynamics could handle.

Diesels more commonly encounter excess over-current readings, at the heads of downhill freight trains...often, the only way to control the train’s increasing speed , as current limiting reduces the retardation,  is the application of the automatic brake valve, and wheel brake shoes ....to slow a train and keep it under control.

Sure, you could put 8-10 dismals behind 4014, but once he got a roll-on and the HP advantage,....he’d be GONE...
TM current limiting is what controls dynamics’ effectiveness —— under 18 MPH, you’ve got enough ‘Grid Capacity” to hold BIG BOY down. Over that—- and you threaten to blow-out the traction motors through over heating.

With conventional freights,  gravity ALWAYS gphas the capability to exceed crankshaft HP. Seriously tyreatening the traction motors.   The energy of the moving train increases as the square of the speed .... doubling the speed, quadruples the Watts generated...you soon hit the point where T/M current-limiting reduces the grid braking to nil.  That’s why, it’s even possible to loose control of a runaway train..the speed down hill and building energy of the rolling mass,  exceeds the capacity of the tread brakes of the wheels to control,the train..
IF Big Boy can get the train to 40+, HE’S GONE...

( This all depends on how good is the design and functioning of the oil-burning firebox —— to produce 5,000 HP  of steam
for the 4 cylinders ... we’ll soon find out, won’t we?). My speculation is that it would take take six months of analysis & mods together with subsequent “train-track testing” to get the firebox, air-flow & burner combination RIGHT.

Its very doubtful that the highly-successful design of firebox, drafting and gas flow will be the outcome of the first attempts...
But, they might get lucky.

​W.



Edited 1 time(s). Last edit at 01/08/19 12:26 by wcamp1472.

"( This all depends on how good is the design and functioning of the oil-burning firebox —— to produce 5,000 HP  of steam 
for the 4 cylinders ... we’ll soon find out, won’t we?). My speculation is that it would take take six months of analysis & mods together with subsequent “train-track testing” to get the firebox, air-flow & burner combination RIGHT. 

Its very doubtful that the highly-successful design of firebox, drafting and gas flow will be the outcome of the first attempts... 
But, they might get lucky."

$100.00 says they will not get it right the first time.....

They already have precedent and design for an oil burning locomotive. At the speeds they'll run and the antipated duty cycle they
will have produced a modern ALCO C855, smoke anybody?

Out

PHall Wrote:
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> How big are the 4-8-4+4-8-4 Bayer-Garrett's?''

I recall an TRAINS magazine article about these Garrett's and how big they were. A TRAINS art director had a broadside photo of a Big Boy with the silhouette of a 4-8-4+484 Garret alongside the Big Boy. The Big Boy was much larger.

Re: callum...

The single ‘experiment’ resulted in how many oil burning duplicates, on the 4000 class?
How many years after the ‘experiment’, did Big Boys continue to run?
Was the oil burner converted back, or was the loco retired, at that date?

​W.

 

> Even with diesels in full dynamic brakes, the
> retarding capacity ( HP ) of the dynamics drops
> off severely, as track speed increases.

Retarding TE, you mean. Braking horsepower
doesn't drop off severely.

Maybe Elwood's site still has graphs of
dynamic-braking-effort versus speed
for SD40-2s and suchlike. About 60000 lb
at 24 mph for one of them, so two of them
would limit a Big Boy to 20 mph or so.

(He has the SD40 graph
http://www.rr-fallenflags.org/manual/sd40s06f.pdf



Edited 1 time(s). Last edit at 01/08/19 14:34 by timz.

wcamp1472 Wrote:
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> Re: callum...
>
> The single ‘experiment’ resulted in how many
> oil burning duplicates, on the 4000 class?
> How many years after the ‘experiment’, did Big
> Boys continue to run?
> Was the oil burner converted back, or was the loco
> retired, at that date?
W

Good questions Wes. UP 4005 was the experimental 4-8-8-4 that was fitted with the oil burning equipment. From what I understand the locomotive didn't survive in this configuration for very long with the uneven heating of the firebox causing staybolt breakage beyond normal levels. So it was converted back to coal and lived out its life like that. 4005 eventually was retired ad now sits in the Forney Museum in Denver, Colorado.

Bob Krieger
Cheyenne, WY

Kratville:

Soon after World War II, a coal strike plagued the nation, so UP experimentally fired a Big Boy with oil to see if it could be done in case coal strikes forced the road to expand oil-fired districts.

A standard Thomas oil burner was installed on the 4005 because it was due for a shopping.  A single burner was used and the only modificationwas the increasing of primary air around the burner.  A special fuel tank was designed at Omaha and built at Cheyenne to replace the coal compartment.  The burner was specially ordered and was the largest available.

From a steaming standpoint, the 4005 steamed better than any oil burning power UP men had seen on any road.  However, the single burner caused spot heating on the huge crown sheet which in turn, caused it to leak.  Every trip was the same -- when you looked in the firebox it was like a rainstorm, with water pouring down so fast that it almost extinguished the fire!   --- Big Boy by William Kratville


Jack / Hotwater:

Yes, everybody ALWAYS refers to that famous Kratville paragraph, when discussing the 4005 oil burning conversion, and her "problems". However, the rest of the story, gotten from those long gone "old heads" that worked on 4005, and fired her, indicate that, once the larger burner was PROPERLY ALIGNED, and MUCH MORE firebrick was added to the firebox, the 4005 gradually stopped having "leaking staybolts". Also, 4005 subsequently wound up being MUCH easier to fire and maintain proper working boiler pressure, than ANY of the oil fired Challengers!

Apparently they didn't want to set up another fueling station which would have been necessary to actually implement oil burning.

Well, then there's this.............

---

If this was a true road locomotive it wouldn't be much of an issue provided you had enough time to work out the bugs,
but this is a let's sit for four hours in Ogden to have a ceremony locomotive. I mused that two smaller burners with a
vertical divider between them to cause some swirl and updraft might make more sense, But I'm sure that Ed wants
something that'll make 8000 hp with 22 passenfger cars behind it and I wish him the best.

Out

If you want to count them, The C&O M-1 and N&W Jawn Henry Turbines both were longer than the UP's 4000's and produced similiar HP/TE.

It's 'than' BTW....

B