When the USRA was around, wasn’t there a requirement for all steam locomotives with a firebox over 80 sq. ft. to have an automatic stoker?
Really interesting thread!
25 tons/hour uphill is a number I recall reading. Speeds varied quite a bit in videos I have of operation on the hill. Manifest trains ran quite a bit faster, drags as slow as 15 mph. Double-heading was also common, sometimes with Gas Turbines in later years.
I recently read about some tests NYC did on 2 Niagra’s, one with 75" drivers, the other with 79". As expected the smaller drivers moved the peak HP to lower speeds, however the larger drivered loco pullled everything NYC wanted it to and did so on less coal and water. Some have suggested that super-steam locos should have been built with smaller drivers, but I wonder what happens to the Big Boy’s steam, water, and fuel requirements if you redid the calculations with 60" drivers instead of 68".
It looks like we’re getting glazed by large numbers. If BB did burn 28 tons of coal per hour, it would have been a hugely uneconomical endeavor.
To give some perspective to this figure, it indicates that the firing rate would be 368 lbs of coal per sq.ft. of grate/hour. This is would be appropriate only for a full-flog, let’s-see-what-it-can-do type of test, if that. Most locomotive tests I’ve worked with do not get over a firing rate of 250 lbs/SF/hr. at maximum output. Over the road is usually under 150 lbs/SF/hr. The lower the better, because combustion and heat transfer take time. The law of diminishing returns is alive and well when boilers are pushed too far up the evaporation and firing scale. You may get more steam (up to the grate limit or evaporation limit), but you will pay for it!
Kratville’s book indicates that sustained over the road performance between Ogden, Echo and Evanston was more like 16,000-19,000 lbs or coal/hr and 70,000-77,000 lbs tank water/hr. How accurate they are, or under what exact conditions they were derived, I don’t know. Nonetheless, this is a far cry from the figures posted on the NPS site and other sources that tout 28 tons/one tank of water per hour. I’m not saying it never happened (never say never), but it sounds like a theoretical value. BB could generate the published 6,100-6,200 DBHP figure (depends on how you read the graph) without going to extreme measures.
Paul-
Thank you for starting this thread.
I hope that during 2006 you find the time to rejoin the forum.
Overmod, RLHainey, I would like to see you guys come back as well.
Good thread - glad to see you guys getting into it.
If you want figures for N&W’s Y6, Louis Newton has them in volume 3 of his Rails Remembered. He was present on dynamometer tests working eastbound out of Williamson to Bluefield. This includes 25+MPH running with 7200 tons up the Tug River from Williamson to Farm, where the train was halved for the trip up Elkhorn Mountain’s 1.4%, where dragging speeds in the 15MPH range were the norm.
In this volume Newton also has data for the three trips between Williamson and Portsmouth with Class A 2-6-6-4 1239 and trains grossing 16,000 tons made in 1952 after the F7s were tested.
Newton makes no calculations or efficiency claims, but his data are precise and very, very interesting. On the dynamometer car runs, coal was weighed in the tenders during the runs (in 200-pound increments) and the water was measured.
All the runs were with the auxiliary tenders, giving both classes of engines 40,000 gallons of water to start out with (22,000 gallons main tender, 18,000 gallons in the auxiliary tender), and no water or coal stops had to be made en route with either the A or the Y6. I don’t have the book in front of me, but as I recall, the Y6 used 35,000 gallons of water on the Williamson-Bluefield run. So if you want to get the book, his data will certainly give you some fresh stuff to chew on.
Old Timer
Asketh Train Guy 3:
“When the USRA was around, wasn’t there a requirement for all steam locomotives with a firebox over 80 sq. ft. to have an automatic stoker?”
I don’t think it was a grate area requirement; it was probably a combination of grate area and weight on drivers. The only USRA designs available without stoker were the two switchers and the light Pacific, which was equipped with a coal pusher. The light Mikes had a grate area of 66+ sq. ft. and they were stoker-fired (the Southern got duplicates in 1923 that were shovel fired). Everything else (heavy Pacifics, both Mountains, heavy Mikado, both Santa Fes), was in the 70-80 sq. ft. range except the Mallets which were, of course, larger.
Old Timer
The stoker requirement was from the ICC in the pre-FRA days. Lenoir Loree of the D&H was miffed by this regulation.
Hi,Oldtimer;; For years I have been reading about N&W "s Super steamers of 1952.Never could figure out why their steam figures were so kept secret. However, your post has revealed a very good insight on the subject of the A & Y6B. Thank you very much. Switch8frg.
Dieselization would have been completed around 5-8 years sooner if WW 2 had not intervened.
The scary part is I have absolutely no backround or training in this type of physics,yet I understand it.
All I know is how a steam loco works.Fascinating stuff.
Sayeth Switch8frog:
"Hi,Oldtimer;; For years I have been reading about N&W “s Super steamers of 1952.Never could figure out why their steam figures were so kept secret. However, your post has revealed a very good insight on the subject of the A & Y6B. Thank you very much. Switch8frg.”
If by “Super steamers of 1952” you mean those class “A1” and “Y6c” engines described by Robert A. Le Massena in a TRAINS article and in his revised book on articulated locomotives, don’t worry. They didn’t exist.
Le Massena speculated that Class As and Y6s were modified to carry 315 pounds of boiler pressure, and the class A frames were leaded like those of the low-pressure engines of the Y5s and Y6s. He was led to this conclusion by his erroneous thinking that the A 1239, in its tests after the F7 tests, performed better than the original A test on the Scioto Division in the Wartime '40’s. In his mind, any increase in performance had to come from fiddling with the locomotive. It didn’t. I refer you again to Volume 3 of Louis Newton’s RAILS REMEMBERED for the straight dope. Newton was present for both the 1239 tests and previous tests of Y6s on the Pocahontas Division.
After Le Massena’s TRAINS article, Newton had a rather extensive letter to the editor rebutting Le Massena’s conclusions.
Old Timer
Hm. I recall a power plant that generated electricity in Arizona using something like 4 100 ton HOPPER cars an hour PER BOILER worth of coal.
You can do a good day’s work with Coal it’s the water that is needed more often. Besides the Big Boy was a specail engine for a special task, running mile long trains over the west where the land is large and strong.
I think there is enough coal under the USA to keep us going for quite some time.
I thought the BB only used about 8.9 tons of coal an hour.
Aaccording to what I was told by a member of the UP steam team this August, a Challenger (like 3985) on a freight train would burn about 20 - 25 tons of coal on the climb from Ogden to Echo Junction. That is a track distance of about 45 miles and based on other information I have heard (not confirmed) it would take between 2 and 3 hours if all blocks were green. This is about 8 to 12 tons per hour.
PS – early stoker fired engines required a fair amount of shoveling to even out the fire and fine tune the firing rate. The fireman also had to pull coal into the stoker if it hung up in the tender.
dd
I want to amplify Old Timer’s comments on the so-called N&W A1 and Y6c’s. The initial article appeared in Nov 1991 Trains. Part of Mr Newton’s reply to that article and Mr. LeMassena’s rebuttal appeared in May 1992 Trains. Mr Newton had considerably more to say in the May/June 1994 issue of N&WHS’s magazine, The Arrow as well as in his book referenced earlier. There was another article in the Jan/Feb 1998 issue of The Arrow which corroborated Mr. Newton’s first-person observations from an engineering viewpoint and rejected Mr. LaMassena’s conclusions. Anyone interested in finding out what really happened needs to read all of these sources to get the story straight. The initial presentation had a several material errors and a significant number of unsupported conclusions.
I was wondering if there were any fast and easy answers to efficiency comps for the largest, and the most successful of the super power steam locos. In my mind, the best of the best considerations must include efficiency, for, after all, the cost of fuel is the single most expensive consummable commodity on any railroad, even today.
Since there are no easy answers to this question, and since a scientific study is at best an arduous, time-consuming task resulting in exceptions, controversy and conflicting data, I propose that the very best solution is to look at how the designers had the tenders built after years of operating experience was able to provide them with all the answers they needed to hook up a properly defined tender(s) to the beasties.
Bottom line, gents: It ain’t rocket science. How much coal each loco typically carried vs how much water, and what were they able to do with it on average in terms of tonnage, speed, and hill climbing was well-defined by experience and design resultants. We need look no further than the tenders.
Big Boy final 5 production loco tenders carried 25,000 gal water and the same amount of coal as the first 20 did - 28 tons, or 56,000 lbs. I’ve never seen a photo with an auxiliary tender behind a Big Boy, so I am going to say the rate of water boiled off as steam per pound of coal burned must then be 2.24 lbs coal per each gallon of water boiled off.
Next, lets look at, say a class A N&W since it is also a simple articulated, and pulls 125,000 lbs, just 10k lbs less at the drawbar than the BB, and runs at comparable speeds. That auxiliary tenders were commonly used behind these “A” locos is well-documented fact, and it is my understanding that they often steamed off another 10-15,000 gallons minimum before exhausting their fuel supply.
Let’s first look at use with only a primary tender situation.
2-6-6-4 A carried 22,000 gal water pr
[quote user=“GT Mills”]
I was wondering if there were any fast and easy answers to efficiency comps for the largest, and the most successful of the super power steam locos. In my mind, the best of the best considerations must include efficiency, for, after all, the cost of fuel is the single most expensive consummable commodity on any railroad, even today.
Since there are no easy answers to this question, and since a scientific study is at best an arduous, time-consuming task resulting in exceptions, controversy and conflicting data, I propose that the very best solution is to look at how the designers had the tenders built after years of operating experience was able to provide them with all the answers they needed to hook up a properly defined tender(s) to the beasties.
Bottom line, gents: It ain’t rocket science. How much coal each loco typically carried vs how much water, and what were they able to do with it on average in terms of tonnage, speed, and hill climbing was well-defined by experience and design resultants. We need look no further than the tenders.
Big Boy final 5 production loco tenders carried 25,000 gal water and the same amount of coal as the first 20 did - 28 tons, or 56,000 lbs. I’ve never seen a photo with an auxiliary tender behind a Big Boy, so I am going to say the rate of water boiled off as steam per pound of coal burned must then be 2.24 lbs coal per each gallon of water boiled off.
Next, lets look at, say a class A N&W since it is also a simple articulated, and pulls 125,000 lbs, just 10k lbs less at the drawbar than the BB, and runs at comparable speeds. That auxiliary tenders were commonly used behind these “A” locos is well-documented fact, and it is my understanding that they often steamed off another 10-15,000 gallons minimum before exhausting their fuel supply.
Let’s first look at use with only a prim
The point is quite valid. NP locomotives had large fireboxes to compensate for the low-grade coal they burned.
Coal BTUs is very important. One of our group was on a steam excursion that performed well until the replacement coal started into the engine and then it became a struggle !
Northern Pacific, for example, used very low grade (sub-bituminous/lignite) from on-line deposits, and so bought steam locomotives with bigger grates/fireboxes than average.
Many railroads designed their locomotives specifically to burn local, available coal; from deposits convienient to the end user railroad. ‘Mine-run’ coal could range anywhere from smaller sizes, to sizes approaching small boulder sizes (ie: basketball sized(?). coal for stoker-fired engines could be in the range of pieces the size of ballast (2" (?), or smaller pieces.
Here in Kansas the Katy(MKT), and AT&SF used local mined coal that was of a poor grade, almost a ‘culm’ [ie: waste] grade because of the way it was found in shallow pockets mixed with soils.