UP 844 vs N&W J611

Doesn't really matter, since the UP converted ALL their FEF-3 and FEF-2 class locomotives to oil burning in 1945.

RickO: good post concerning the C&O Lima Lawsuit. I'm a close friend of 2 old C&O Steam Locomotive men, and one retiring as a Division Superintendent, the other with 50 years in engine service, both in their late 80's, and mentally sound. They ran and had experience on everything that C&O had back in the day, and said there wasn't a better Locomotive on the roster than an H8 or J3a Greenbriar.  Mr. Harris ran the H8's from Russell, Ky to Toledo,Ohio. and said that when he got it out of the belly of the Ohio River basin, she would absolutely stretch her wings and fly. Said he pulled a troop train north once with one, probably nobody but his fireman would believe what speed it got to, and had throttle lef,t as well as much adj on the reverser.  said the engine would smooth out at higher speeds not unlike the Greenbriar. Man I would have given anything to have experienced what Rich/Hot Water, and my old railroad buddies have done. Their endevors suits me, and I'm hard to please.

I don't have a dog in this fight, but just from reading through this topic out of curiosity, there seems to be a lack of consistent logic applied by the various posters.

In the 844 x J611 comparison, the logic seems to be each locomotive has its own strengths and they are better for each railroad that used them.

Yet when talking about the Big Boy x Allegheny, some posters are saying the Allegheny is better than the Big Boy, and it is the C & O Railroad's fault they didn't use the locomotive correctly.

If you apply the logic from the first example, then the Big Boy was a better choice for the UP, and the Allegheny wasn't as good a choice for the C & O because, not knowing one way or the other myself but according to this post, the C & O wasn't happy with the Allegheny.

The C&O was quite happy with the Alleghenies. However, they never used them properly. They were high-horsepower locomotives that, if given a chance, could run a big freight train at passenger train speeds.

Instead of assigning them to manifest freights where they could put all that horsepower to work, the C&O loaded them down with monster 15,000 ton coal drags and ran them like a drag freight engine.

Running at slow drag freight speeds, they simply were not getting the horsepower they paid Lima to produce for them.

How the C&O Allegheny got into this thread makes no sense to me.

It seemed we were discussing the merits of the UP 844 and the N&W 611: locomotive vs locomotive and then railroad vs railroad (UP vs N&W).

Clearly, as far as steam locomotives go, at the end of the steam era, UP and N&W were top players. How did C&O get into the mix?

RickO's fault, then Rich for stirring him up turnin him loose!       ....Brandy

Rich, thanks for the explanation.

Seems there must be a pent up demand for an Allegheny thread around here....fully understandable once you've stood next to the H8 at Henry Ford / Dearborn.  A locomotive where you can literally see the Factor of Adhesion...literally !

611 does have one thing going for it.  Lionel did make a "model" of it, (Note the ""!), and that does help her exposure to some people.

For me, I like BOTH.  Both have clean lines.  Both were the best 4-8-4's for each respective railroad.  

Long shot, but with these two, at least, one could have a "steam off":  Set of test, with both of them running under test conditions on each road.  But it will NEVER happen.

The "model" I was speaking od was the late 1950's PW one.  But, yes, I have seen the Lionel FEF, and it does look great!

Santa Fe did the same when Baldwin was building new engines for them.  I would expect that any Class I railroad would have its Mechanical Department representatives on the erecting floor of the builder during the manufacture of any new steam locomotive they ordered.

"Does kinda make you wonder how 844 would have done on N&W's metallurgical coal as opposed to that UP Lignite from Hanna."

I expect that the design engineers of the UP and N&W took into account the caloric value of the coal each railroad was using when they wrote their specifications for each of the locomotives. Thus the lower caloric value of the "Thermal Coal" which is most abundant in the USA should be negated by design.

As each locomotive design was likely tailored to their respective railroad's intended use and probably not many steam locomotives had the same specification, it is difficult to make a performance comparison between the J and the 844. Even the standard USRA locomotive designs were tweaked to suite individual railroads.

Somehow I don't think the Union Pacific burned lignite.....believe it was good old bituminous. The NORTHERN Pacific burned lignite, with diminished horsepower production in their enormous and otherwise excellent steam locomotives. Excellent? Who had the longest single engine coal-burning steam locomotive run in the US (and the world)? NP - Twin Cities-Livingston, MT. 

Actually, Hanna coal is Bituminus by nature...and about as close to Lignite as you can get, and not be the real stuff.  Check the DBHP of the Z6 Challenger when she ran Lignite, and then was converted to a two burner oil rig. No surprise that Uncle Pete went oil as early as 1945 !

Jaygee,

Where can one locate those differing horsepower figures for the NP Z-6's after their conversion to oil?  I don't recall the NP converting any of their Z-6's to oil.  2 of them ran on the GN on oil.  Maybe that's where the figures change?  SP&S also ran some Z-6's using oil I believe.

Steve

The UP generally converted PASSENGER steam locomotives to oil burning (bunker C).

Plus, I'm not aware that the Northern Pacific ever had any oil burning steam locomotives, especially 4-6-6-4s. The SP&S, however did have the oil burning Challengers from the GN, who didn't care for them.  

The two NP-design oil-burning 4-6-6-4's (4000 & 4001) that carried a Great Northern goat herald were purchased from the SP&S so as to comply with an agreement wherein NP and GN rotated over something like 2 year periods, providing the SP&S additional locomotives. The SP&S was jointly owned by the NP and GN.  The SP&S owned a number of oil-burning NP design Z6 and Z8 Challengers outright. The GN Challengers also ran down the Great Northern's Oregon Trunk (Wishram, WA to Bieber, CA) but only as far as Bend, OR. Don't believe the Challengers ever made it all the way to Bieber, CA (WP interchange); the photos I have seen at Bieber were of GN 2-8-8-0's, R1 2-8-8-2's and 2-10-2's.

         Bob LaMassena, the steam locomotive "expert", speculated that SP&S Challengers produced much greater horsepower then their "dirt burning" NP cousins. I have never seen dynamometer tests for the oil burning Challengers. Did see actual tonnage ratings, for the Oregon Trunk, and the Big G's R1's outpulled the oil-burning Challengers. On a 0.4% grade, the GN determined that the 4000/4001 could pull 7000 tons, N-3 2-8-8-0 7856 tons, R1 2-8-8-2 9310 tons and the GN's biggest steam locomotive, the R2 2-8-8-2, could pull 10,000 tons. The GN's estimate of cylinder horsepower for each of these locomotives was Z-6 4050, N-3 4200, R-1 4370 and R-2 5193. Don't know what formula was employed for these estimates, perhaps just "back of envelope". Data taken from "Steam Locomotives of the Great Northern Railway" by Middleton and Priebe (2010).

I figured that NP was the conversion source for oil, but if not....it still happened. As for TE. values and tonnage ratings in the mountains...this may have been effected by DBHP, but more than likely not.  Case in point: N&W.  Y6 (a&b) vs. Class A.  The A had the higher DBHP, but lower TE. and lower tonnage ratings on the same grades. The point is better fuel = more flexibility in designing the locomotive.....and yes oil can certainly be considered a "better fuel".

It would seem realistic that if a steam locomotive operated at it's design boiler pressure, it would produce it's power potential. But, I was quite surprised to read the results of dynamometer tests (08-05-42) of Northern Pacific's A-4 class 4-8-4. The test quoted speeds to a maximum of 51 mph and a drawbar horsepower of 3860 at that speed, which was the highest output in the test. The highest indicated horsepower for this locomotive (#2670) was achieved at 42 mph and was 4646. I believe indicated horsepower occurs before the locomotive has hauled itself around. I found those results rather disappointing for such a large locomotive with a huge firebox (115 sq feet). This contrasts with an indicated horsepower rating of 6610 at 85 mph and a drawbar horsepower rating of 5050 at 62 mph, for a NYC Niagara. I will grant that the Niagara was a superlative design, but the NP locomotive was not that far off the mark.

        Even more disappointing were the dynamometer results for the NP Z-8 Challenger. It produced 24% more indicated horsepower at 37mph - approximately 4999. That's "indicated", not drawbar horsepower. Again, Robert LaMassena attributes the diminished power output of Northern Pacific locomotives to the low BTU content of it's "rosebud" coal, which came from company mines in Montana. Now this represents my rather frail grasp of physics, but if horsepower is a measure of work performed in a measure of time, it might stand to reason that the power released in a period of time from lower BTU fuel would produce less work, again, in a measure of time, held constant. Higher BTU bituminous coal would release more energy, convert into more steam, which would, in turn produce more work per unit of time, no? This test data was obtained from "Northern Pacific Supersteam Era, 1925-1945", by Schrenk and Frey (1985).

Ah, the N&W Y classes have the higher TE. not lower.   126K at best for the A Class vs. 152K (as built in '48) for the Y6b. Other Y6 classes rated the same. Later upgrades brought the Y5-Y6 Classes up to a staggering 170K.  In compound operation, they went from 126K to about 132K by 1953 or so. Tonnage ratings would clearly reflect this, either east or west of Roanoke.  And so why would an oil conversion work out so well on the Z6?   I'm postulating two thoughts here. Two burner installation, and better use of the available free gas area throughout the firebox.  OTOH, if the whole affair was a basket case, then why bother keeping it in service (Z6 ...oil)? 

It would appear that the Z-6's and Z-8's worked fine on the SP&S, as they remained in service from the late 1930's to 1956. Oil as a fuel would work out better if it contained higher BTU content, or power potential, to produce greater steam force/volume. Don't know the precise stats but suspect that oil has a higher BTU content then NP Rosebud coal. As does bituminous.

Mark,

Remember that "oil burning" steam locomotives were actually using Bunker C, residual for fuel. I sure don't know what the BTU per pound of that crap was, but it had to be heated to over 150 degrees to even get it to move, and was usually heated to well over 175 degrees.

Mark_S

  I'm headed to Roanoke Thursday and will try to look up both the GN and NP sources that you mentioned.  The N&W Historical Society Library has an extensive collection of books, and both of these references are there (IIRC, a dicey proposition as age creeps into the equation).  The various cylinder HP figures you cited don't entirely add up based on the CHP formulas I have, so I don't know what to think.  We'll see  maybe Sunday or Monday next week.

The "cylinder" or "indicated" horsepower (same thing) is measured by the use of an "indicator card" that measures the mean effective pressure in one cylinder of a locomotive. (Most tests used indicator cards on both sides of the engine). The MEP was measured to "point of cutoff", and the card would show this. Cards were taken at both ends of the cylinder. A photo of an Indicator card is on p. 60 of Staufer's "Thoroughbreds". The speed of the locomotive and the cutoff  at the time that the card was taken was noted. Both ends of each cylinder times 2 cylinders is "cylinder horsepower" for a two cylinder locomotive.

Drawbar Horsepower is the amount of "pull", in pounds, at the coupler at the rear of the tender, and the speed at which this "pulling force" occurs. This is usually done with a dynamometer car. PRR was an exception. What PRR did at the Altoona test plant was to measure, with the engine driving wheels on rollers, the pull at the engine's drawbar, ignoring the weight and resistance of the tender and with no deduction for wind resistance since the engine was not moving.

Unless the track was both level and straight and the acceleration (but not the speed) was held to "zero", corrections were required to obtain true drawbar pull. That is why NYC used a "brake engine" behind their dynamometer car to hold the speed constant, and could easily replicate multiple readings at any speed.

So DBHP is calculated as Pulling force (in pounds) x speed (in MPH), divided by "375". (The "375" is called the "horsepower constant", and is derived by the conversion of "one HP = 33,000 pounds hoisted one foot in one second".) (To correctly calculate DBHP, acceleration has to be held to "zero" since it takes more horsepower to accelerate, just like your car.)

For example, if a locomotive can pull with a force of 16,000 lb. at 100 MPH, its drawbar HP (AT 100 MPH) is 4267. (By the way, to my knowledge there were only two steam locomotives that could exceed 4000 DBHP at 100 mph, a PRR T-1 and a NYC Niagara.)

I have several test reports from the Altoona Test Plant, and it appears that PRR was mostly interested in boiler performance and the coal and water rates. For example, the Plant started to record drawbar pull at 35 mph, believing that lower speeds would  damage the plant's rollers, and "drew" the remainder of the pull curves to "zero speed" by "filling in" the curve below 35 mph. Since the "general" speed limit of PRR trains in the steam era was 40 mph, the curves were almost useless in determining over the road performance.

The weakness of a steam locomotive was that it produced its maximum HP at one speed. A diesel has an "almost constant" horsepower throughout its entire speed range, so its "average horsepower" during a trip is usually much higher than a similarly rated steam locomotive.

Hudson5432:  What is an "indicator card"?  What is "MEP"?

FeltonHill:  What is "IIRC" and "CHP"?

PRR test plant figs are only good for other PRR engines tested at the same plant in the same way.....and useless for all else. Case in point: the Q2 class was good for 7900 HP on the plant equipment, the J1 about 1000HP less.  In OTR testing, the actual difference was about 275HP !    It's interesting to compare the Q2 / J1 to the SD45 /  SD40 performances of twenty years later.  For 600 more ponies you got a high maintenance fuel hog, while the "lesser" chooch set the standard of the era.

A good read would be the testing of the Pennsy's T1 and the N&W's J in June of 1948, which was re-published in the NWHS's "The Arrow"....interesting to say the least.  I'm going to have to find my copy and post some numbers.

Hudson5432 defined "MEP" in his post: Mean Effective Pressure.

"CHP" has also been defined in other posts: Cylinder Horsepower. I would also use it for "Calculated Horsepower."

Hudson also explained briefly what an indicator card was--basically a graph showing what happens in a cylinder as it cycles back and forth. Rich explains it a little about half way down in this thread.

"IIRC" is "If I recall correctly." It's Internet shorthand that's been around for ages, FWIW.

The Keystone, on the PRR side had the testing of N&W 610 on the PRR.

The Keystone also had the PRR T1 tests on C&O and N&W in the same article in a different issue.

The cylinder horsepower (CHP) figure I was thinking of is one that was calculated as follows:

(cylinder bore/2)^2 * pi * boiler pressure * 0.0229, which is a constant of some sort for superheated locomotives.

Many railroads used this to calculate CHP on their locomotive diagrams, C&O being one that comes to mind.  In words the formula is:

cylinder piston area times boiler pressure times a constant.

In my opinion, it doesn't mean very much and certainly doesn't seem to reflect any horsepower characteristics.  In any event, this is what I will try to look up in Roanoke later this week for GN and NP.  They may use some variation of this, or the figures could be from  actual test data.  If that's the case, Hudson5432's earlier explanation  of CHP and IHP is accurate.

I have yet to get my hands on a copy and read that..I sure would love to.  Someday I'll get my backside in gear.  I've heard the basics but I need to read that for sure.

And a N&W "J".

The NP and GN horsepower data I quoted provided no explanation for the actual formulation employed in deriving those horsepower measures. The NP data was a retelling of dynamometer test results. So guess they have to be taken at face value.  The Great Northern measures look pretty much like the old "back of envelope" method wherein the grate area is multiplied times 40%. The N3 2-8-8-0 had only 95 sq ft of grate, so I think the estimator was giving additional credit to that locomotive's 300 psi boiler pressure. As always, calculating steam locomotive horsepower is a squirrely affair!

CWEX,

The horsepower curve for the N&W J published in Railway Mechanical Engineer along with its N&W author, Pond, has the drawbar HP at 100 mph as 3150.

mark s.

I have the NP book NP Supersteam Era by Frey and Schrenk, and the title of the HP chart on p. 136 for the NP A-4 class 4-8-4 is "Indicator Card Tests", and this would occur in over the road testing, not using a formula. The text refers to the use of a dynamometer car, and this is supported by the information in the Table. Although these engines had pretty large drivers, 77", the speeds for which DBHP is quoted, a maximum of 51 mph, might indicate that the engines were below their speed range for maximum drawbar horsepower. I believe that the low quality coal may have impacted their output.

Sure... if there is evidence to support that the boiler pressure was lower than the normal working pressure for the particular engine, during the tests.

Hudson - By gosh, you are right! "Indicator Card Tests" is what it says. But in the Note section, it is declared that the ratings were taken from over the road dynamometer tests. Additionally noted was that "the locomotive (2670) was steaming freely, the valves were correctly set, and the locomotive was producing the best combination of speed and power". It was operated in the 257-260 boiler pressure range, which was it's prescribed setting.  Agreed, that the 77" drivered machine may well have been operationg below it's maximum horsepower output speed. But, it has been pretty widely observed that NP locomotives did not produce the level of horsepower that one would expect from such a generously proportioned 4-8-4, and it has been generally blamed on the low BTU content of the Rosebud/lignite coal employed.

        It should be noted that the NP did not seem to be disappointed with the Northerns', Yellowstones' and Challengers' performance. The NP's operational goal was to run 4000 ton freight trains across the entirety of their railroad, which these locomotives accomplished. It should also be noted that Bozeman Pass helpers operating out of Livingston sometimes got bituminus coal to improve their power on the grade.

         An interesting operational tidbit: the NP ran a 4500 ton company coal train out of Colstrip, MT every 2-3 days, pulled by a Challenger, to disperse fuel to all intermediate terminals. Canadian National did the same, running "OCS" (On Company Service) company coal trains, pulled by 4-8-4's, dispersing coal brought over by lake boats. 

Hudson5432, what issue of RME was the curve published in?  I have a reprint of an earlier article from 1945, but it was before the 300 psi tests were run.

The 3,150 dbhp at 100 mph for the N&W J is a "theoretical" value developed by N&W.  This is spelled out on the original graph from a series of tests in August 1945.  Sometimes, the note is removed and a reader will be misled into thinking it's an actual performance curve.  However, it's calculated using the Baldwin method. The shape of the curve is the giveaway.  It shows a fairly steep rise at low speeds, a sharp maximum peak, then a relatively flat decline as speed increases.  Actual DBHP curves don't have this shape.

The Baldwin method is also very conservative.  For example, using it for a NYC S1b gives a maximum dbhp of about 4,200 to 4,300 at 45 mph,  lower than the figures developed from actual tests.

The following link displays the heat content of various fuels:

http://people.hofstra.edu/geot...n/energycontent.html

GNNPNUT