Hello!
I am interested in great american articulated steam engines such as:
2-10-10-2 Virginian class AE
2-8-8-8-2 Erie class P-1
2-8-8-8-4 Virginian class XA
2-8-8-4 NP class Z-5
2-8-8-2 D&RGW class L-131, L-132
2-8-8-2 C&O class H-7, H-7-A
What issues of Railway Mechanical Engineer (or another magazines and books) has information about this great locomotives?
Valeriy.
I would hardly consider the Triplexes to be “great” articulated locomotives. Large, to be sure, but hardly great. Both suffered from too much machinery and not enough boiler. The Virginian XA was an unqualified failure and wound up having its running gear used for two new locomotives.
Erie class P-1 and Virginian class XA has unique Triplex system. P-1 has 160 000 lbs tractive effort (see p. 197 Articulated Steam Locomotives Of North America by Robert A. LeMassena, Vol.2). I think it is enough to say this is a great powerful steam engine.
Valeriy.
[swg] Valeriy; maybe ~ Train Shed Cyclopedia No. 47 from Gregg would help you for the info you want. Possibly your LHS could get this for you.
Respectfully, Cannonball
Valeriy–
There is a huge difference between calculated theoretical maximum tractive effort and the actual real world performance of articulated steam locomotives.
Some of the engines you listed couldn’t even produce enough steam to keep the engine running down the track at a respectable speed with a train, and thus were pretty much total failures and were scrapped early.
Exceptions:
Virginian AE Class 2-10-10-2. 176,000 pounds tractive effort. It actually did have lots of usable tractive effort, and had a long productive service career, but they just weren’t very fast at all.
If you want to discuss the best of the American articulateds, I think your list would benefit from some additions or modifications. I would suggest adding the following engines:
N&W Y-6B 2-8-8-2. 152,206 pounds starting tractive effort, simple, without booster. Allegedly 170,000 pounds in the final, upgraded version with booster, but records are questionnable. The ultimate compound articulated! Efficient and productive. Two of them could start a 10,000 ton train on a 2% grade in the rain! Also produced a very serious 5500 actual drawbar horsepower at about 25 mph.
UP Big Boy 4-8-8-4. 135,000 pounds starting tractive effort, calculated. Actual performance was measured to exceed that figure. The last UP test with a dynamometer car yielded an astounding 6290 drawbar horsepower after starting a heavy train on a grade.
N&W A Class 2-6-6-4. Very respectable starting tractive effort combined with outstanding 6300 drawbar horsepower at reasonably high speed. Some consider it the greatest all around running
Adjectives such as “best”, “most”, “biggest”, and “great(est)” really could do with some negotiated agreement as to their meaning.
Was not a simple Challenger great? How about the trusty USRA 2-6-6-2 and 2-8-8-2? Why were they not worthy of being called ‘great’? I would list the A Class as an honourable mention at the very least.
The Yellowstones were ‘great’ articulated engines surely. And I would agree that the rather smallish articulated Y series from the N&W were worth inclusion on such a list.
-Crandell
According to Huddleston, the USRA 2-6-6-2 was regarded, even during its era, as nearly a “failure” in comparison to the much more successful and powerful USRA heavy mallet 2-8-8-2. Only 2 railroads bought them, and even though C&O built 10 late copies, they were primarily to replace worn-out locomotives on mine branch line service–where they were ideally suited.
Huddleston, in his book, did attempt to address Crandell’s comments. Also, he was talking about the “World’s Greatest”–but he did say that all the engines in his top ten list were great engines.
The top ten engines included the Yellowstones, both DM&IR and NP versions, and the NP Challenger, along with the WP 257 Class 2-8-8-2, and I believe the B&O EM-1 Yellowstone.
The Rio Grande L-131 2-8-8-2 was left out because the list was limited to “engines built after 1930” and it was a bit too early, and not quite as powerful as the WP 2-8-8-2.
I think Huddleston’s main emphasis was on Superpower ie horsepower at (more than drag freight era) speed–and engines that had all the most modern equipment–though the engines with high starting tractive effort did all rate well.
Many folks love the UP Challenger, but in this comparison it does not rate quite as highly as some other engines because WM, NP, and DRGW all had challengers that produced more tractive effort and/or more horsepower at speed. The UP engine was certainly a fine and versatile design, and served quite admirably in just about any service they assigned it to, but Huddleston’s point of view is that other Challengers, at least in terms of power output, were superior machines to the UP version. Rio Grande most certainly preferred their own design (with 8000 pounds more starting tractive effor
Nobody’s going to mention the SP’s cab-forwards, AC-4 thru 12? They were very useful and versitile, perhaps the first articulateds to be equally comfortable running in both passenger and freight service. Not quite as heavy as some of the others mentioned, they packed a decent amount of tractive effort and you couldn’t beat them for visibility. One development of the type, the AC-9 was actually built to run the conventional way because it was originally a coal burner. With a neat skyline casing and an all weather cab, it may have been the handsomist of all the articulated types. And one other one - the American Railroad of Puerto Rico’s Baldwin 0-6-6-0’s of 1904. Thiese engines were meter gauge and had the distinction of being the very first articulated mallets ever built in the United States. B&O’s “Old Maude” was just an upscaled version of this engine.
The 6,290 HP for the Big Boy came from only one locomotive in one test. Collectively in tests, the Big Boy’s were more like 5,800 DBHP engines.
To my knowledge, there is no N&W test data or documents to support the 6,300 DBHP claim for the Class A. The N&W never claimed that much HP from an A. In fact, the only people who make that claim are railfans. I have no idea where they got that figure other than out of thin air.
The Allegheny’s 7,498 DBHP was from a test where the dyno readings were bouncing around like crazy. The data points were all over the place. A best fit curve shows the actual DBHP to be around 6,500 at that speed, which is still far above any other steam locomotive.
Do you know where the best fit curve for the Allegheny was published?
Also–steam locomotive test data is only as good as the job the crew was doing of running and firing the engine.
Though the Big Boys evidently performed well, there seems to be some evidence that the UP Challengers steamed better throughout all speed ranges–or rather that on sustained grades the Big Boys tended to slow down a bit and apparently could not produce quite enough steam. Perhaps the variation in Big Boy numbers has something to do with the challenges posed in firing them?
John
All these large locomotives had automatic stokers, although operating them certainly required skill. I don’t think the Big Boys’ slowing down on hills had anything to do with a lack of performance. They were rated as more powerful locomotives, thus had longer and heavier trains to pull, and the heavier the train of course the slower the uphill climb. Possibly loading them to their capacity was more routine than with the Challengers.
Huddleston states in his book that the Big Boys were more difficult to fire than the Challengers, and it was Huddleston who suggested it seemed the Big Boys were unable to produce quite enough steam at speed on heavy grades. According to Huddleston, UP’s design goal was to achieve 25 mph unassisted on the Eastbound average 1.14%, 24 mile grade over the Wasatch–which they apparently did not quite achieve. Eventually, two Challengers with about 70 car train lengths proved to be the ideal choice over that division–till the end of steam.
Even though all the big articulateds had stokers, some were easier than others to fire.
Kratville also says in his books the Big Boys were more difficult to fire than the Challengers. Also, when converted to oil, the Big Boy (#4005) did not perform very well at all, whereas the Challengers converted easily to oil and steamed quite well.
John
They did claim it-- as I recall they claimed it for the 275-psi engine. You remember they also claimed it pulled 7500 tons at 64 mph on the level, which would be even more impressive.
I found a lecture presented by Robert M. Pilcher 3/12/53, at that time Assistant Engineer of Tests for N&W. He had this in his script:
“Under unusual spot conditions dynamometer records a maximum sustained horsepower of 6300 at 45 mph.” [He did not specify boiler pressure for this reading, but other sources indicate that it was 275 psi. No test report has been found yet]
“In usual day to day operation, the dynamometer record indicates drawbar horsepower between 5200 and 5400 over long distances at speeds between 35 and 40 mph while handling 175 loaded trains over almost level track.”
These figures occur frequently in N&W public statements and articles written in the 1940s-50s.
My copy of Huddleston’s book is loaned out to a friend, so I can’t find the source he may or may not have cited for the 6,300 dbhp figure for the A Class.
Regarding the SP Cab Forwards mentioned above: They were surely great engines, and I’m not sure if the starting tractive effort was high enough to get them onto Huddleston’s “top 10”. It may have been the engine I left out.
Again–my copy of the book is loaned out, or I could look it up.
Sorry for the confusion.
John
To the original poster, Valeriy–
If you check the used book market, there are some fine books regarding the various engines you mentioned.
There is a book devoted entirely to the H-7 Class.
There is a book called Northern Pacific Super Steam Era.
There are books by Robert LeMassena. I think the titles are: Articulated Steam Locomotives of North America, Volumes 1 and 2.
Respectfully submitted–
John
Timz,
Three bits of information stick out here: “under unusual conditions”, “no test report has been found”, “in usual operation dynamometer records indicates drawbar horsepower between 5200 and 5400”
That’s why I made the statement, to my knowledge, no records exist of a Class A producing 6,300 HP. The “under unusual conditions” and “no test report found” raises more questions. There are plenty of N&W sources stating the 5200 to 5400 HP figure however. Who knows, maybe under the right conditions, the A could produce 6000 HP, but I have found no records to indicate it.
What I find interesting, if my data is right, is the Class A didn’t have any more direct heating surface than the Class J (580 sq.ft. vs 575 sq.ft) and lacked thermic syphons and circulators. By comparison, the two other large Eastern simple articulated locomotives, the H8 Allegheny and EM1 both had 760 sq.ft. direct heating surface, thermic syphons and circulators. Perhaps feltonhill can comment on this aspect of the A’s design.
The N&W Class A had 530+57 SF (firebox+circulators) of direct heating surface vs the J’s 518+60 SF of DHS, relatively close. These are as-built figures for 1200-1237. The A relied more on its indirect HS, which was significantly larger than the J (6,063 vs 4,693 SF). The final order of A’s were equipped with six circulators as built instead of arch tubes. Based on photos, at least 15 of the older A’s were retrofitted with circulators. There may have been more.
Something about circulators, arch tubes and syphons has always bothered me. By industry standards, they are considered part of direct heating surface and are used to estimate DHS evaporation. Yet I’ve always wondered if they have the same heat transfer capability as the firebox sheets. It seems that the water velocity through these additions would be very rapid, much more so than the water surrounding the firebox. Could it be that arch tubes, circulators and syphons are “less equal” than firebox sheets in terms of heat transfer per unit time? Circulators and arch tubes have a relatively small contribution to DHS, but syphons have a much larger effect. If so, locomotives equipped with syphons would seem to have a falsely large advantage over those equipped with circulators as far as estimated evaporative capacity is concerned. Anyone know if this is the case?
Be back later.
Didn’t the UP steam-crew removed some of the T-circulaters of 3985 firebox without any known power loss? Hard to say for me, if these are anyway valuable in a oil-burning firebox.
For Valeriy:
here you may find some notes about the Virginian AE and more about its railroad ops…
http://www.catskillarchive.com/rrextra/ngstory.Html
See page 366 ( picture of an AE blasting out of a tunnel )
P. 370 Virginian hauling 17.500t record train in 1921
P. 378 Pic. of the largest iron horse
The AE class set many records:
most weight on drivers
largest boiler diameter
largest low pressure cyl.
highest starting TE of two coupled artic. engines
Cheers
lars
When converted to oil, Kratville says they were steaming best. The leaking problem was another one, but not the steaming capabilities.
lars