That 2-12-4 is just too cool for words!
What wouldn't we give to see the UP 4-12-2 9000 running again?
Just two chances of that happening however, slim and none.
Sigh.....
2-12-4 broadside view - 52.8 inch drivers - tractive effort of 78,216 lbs - boiler pressure of 232 PSI - appears to be the two cylinder model - constructed 1931...
I knew it was in one of the former Warsaw Pact countries. Bulgaria? Cool!
Shows that love of steam knows no borders. Maybe THAT'S the way to world peace? Get the steam freaks in power, everywhere.
I will admit I am new to railfanning. However seeing what they did in the 30's and 40's makes me realize one thing. How good the Enginners that came up with this stuff were. You think about HP some of these large steam engines produced and did for hours on end during WW2 moving all the goods we needed to win that War that was fought not just in Europe but in Africa Asia the Pacific plus we fed the Soviet Union had to build the shipping to counter the U Boats all the trucks tanks and planes we made. What we did back then was unbelieveable. You think about this there was only what 25 of the 5011 class made for the ATSF total 25 Big Boys and those 50 engines kept 2 of the hardest divisons in Railroading fluid pretty much on their own if you think about it.
kgbw49Overmod - That diagram is fascinating. Is it somehow a precursor to the C&O Allegheny 2-6-6-6 locomotives?
In a very real sense it is more an antithesis to the Allegheny in almost all respects except the idea of a very large firebox and radiant area feeding the largest possible boiler that fits effectively into the loading gage. The 2-12-6 had a larger grate area than the Allegheny, although the firebox structure may have weighed somewhat less 'per square foot'. You can think of the 'engines' as being a practical version of duplex (divided) drive, as in all probability the 2-12-6 would have required either 15" or larger valves or some variant of David Wardale's double piston valves to make best use of its cylinder capacity.
While the 2-12-6 need not have been a slow locomotive, I suspect its effect on track geometry would not be particularly good. Remember that the UP Nines were three-cylinder power with reciprocating mass that could be relatively effectively balanced as in Swiss drives -- that wasn't the case for Woodard's design, and moving heavy rods inboard will only get you so far.
On the other hand, one of the very worst things that made the Alleghenies so overweight was the complicated system of admission and exhaust piping needed to implement the Mallet-style drive -- that's a LOT of pipe shoehorned in to do the job of some comparatively short pipes and tracts on a 2-12-6...
Also, I believe there might be a 2-12-4 tank locomotive that is actually restored and operating in one of the former Eastern Bloc countries across the pond.
Bulgaria.
Other 12-coupled classes (including one Nine) survive. At least one (the Javanics) were developed due to steamline problems with contemporary Mallets. Might have been more had there not been a Herb Garratt...
I believe that 2-12-4 (Wow! I'd love to see THAT!) might be operating in the Czech Republic. I'm sure I've seen some YouTube video starring the same.
Overmod - That diagram is fascinating. Is it somehow a precursor to the C&O Allegheny 2-6-6-6 locomotives? Also, I believe there might be a 2-12-4 tank locomotive that is actually restored and operating in one of the former Eastern Bloc countries across the pond.
Dr DSCULLIN, BOXPOK, Baldwin Disc, and Universal drive wheels these were not cosmetic styled wheel sets applied to steam locomotives of the Depression and War years - they were necessary engineering advancements, changes to bring in the modern age of steam power. And part of this key design change was in the wheels.
Less of it where you think, though. While the disc MAIN was significant in the rebalancing revolution of the latter '30s, it is more important to get good pin fits and lack of distortion in the rim than to have 'increased volume for counterbalance mass' (I will take this up in greater detail looking at the example you quoted from Johnson, below).
The critical thing was the REDUCTION of revolving and reciprocating mass, not the BALANCE by adding more weight, either in counterweights to relieve the 'underbalance' inherent in operation at higher cyclic rpm and high piston thrust, or in increased use of cross-balancing masses at 90 degrees or 'angled' in the wheel structure. And you could accomplish this quite nicely ... at lower unsprung mass, which is increasingly important at higher speeds ... with spoke drivers (and this was the logic behind the Web-Spoke, which was happily used to replace both Boxpok and Scullin centers toward the practical end of steam)
What's important are two things: You want an absolute reduction in the mass of the rods, pins, etc. that constitute vertical and longitudinal inertia force on the drivers (and suspension and wedges respectively), and you want to bring the centerline of mass of the rods as far inboard as possible. Upon this hangs a tale of forgotten lore ... what was Will Woodard doing in that interesting period in the late '20s between the first generation of SuperPower drag hogs and the development of the AMC Berks and then T1 2-10-4? And the answer is fun, if more than a little Teslaesque mad-science engineering... google 'unitary machinery support' and observe some results
This is the thinking before Eksergian et al. and the development of better alloy steels and rod designs to take advantage of them (or at least the willingness of railroad locomotive designers or purchasing agents to pay the additional cost to get them!) - so we adapt the design to reduce inertia forces on REALLY big pistons by moving their centers closer inboard, and do some fancy things with the tandem rod drive...
This is still very much the age of 4-8-4s being heavy and slow power, and articulated Super-Power still being explicitly compound and UNboosted for reasonable balance running compound at speed.
The revolution in high-speed articulateds, of course, actually predates the high-speed 4-8-4 (by a couple of years) and it is interesting to see the line of development that UP and then ATSF take in actually achieving high-speed eight-coupled locomotives. A couple of the approaches being VERY critical, and not really predicted before experimented with... and there is of course the rather dramatic cautionary tale of the ACL R-1s.
Note that the 2-10-2 example is the wrong thing entirely ... invcluding the detail in Johnson's analysis that some of the 'underbalance' was the result of balance lead being improperly cast or positioned and breaking up and pulverizing due to the augmented road shock at higher speed. Here you are compensating the wheel weights up to the heavier weight of existing (excessively heavy and broad) rods, pistons, packing etc. in a chassis that inherently suffers badly from yaw coupling and has a minimum of effective guidance assurance from its trucks. You can reduce the percentage of augment forces with effective cross-balancing, but you are far from having low overbalance and hence the actual forces not of the large piston thrust and inertial mass involved are high (and becoming dramatically and perhaps nonlinearly higher with incremental increase in speed).
If you have not read the CSR white paper on steam-locomotive balancing you might find it of interest. I don't think we've discussed their series since you've been 'on the forum'.
------------- Ralph P. Johnson locomotive design engineer for Baldwin Locomotive Works in his book THE STEAM LOCOMOTIVE discusses the all critical engineering changes in the development of improved locomotive drive COUNTERBALANCING.[/quote]
ADVANCED DRIVE WHEEL DESIGN AND THE 2-10-4 TEXAS TYPE
LIMA "Super Power" the name still rings in our ears generations after the advertizing department for steam locomotive sales came up with the "monkier." Starting with the NYC H10 super "Mikado" 2-8-2 and moving to the real game changer, the LIMA A1, soon to become NYC "Berkshire" 2-8-4. Yes, LIMA had the future of steam locomotive design in hand.
Following the A1 2-8-4 "Berkshire" the game was quickly on to the 2-10-4 "Texas" type sold as the famous Texas & Pacific Railroad as, the TP 600 class of freight locomotives. Design had outstripped technology and the super engines were not all they were cracked up to be - pull yes the could - but get them over the speed of about 35 mph and they famously bent the rails on the tracks they ran on. Slap a speed limit on them - yes - but something else had to be done.
Santa Fe had for good reason held off on the development of the 2-10-4 design because of the massive drive rod weights and wheel sizes the engineering of the early 1920's was not prepared to deal with - it was the massive forces of COUNTERBALANCE the locomotive drive generated.
------------------
SCULLIN, BOXPOK, Baldwin Disc, and Universal drive wheels these were not cosmetic styled wheel sets applied to steam locomotives of the Depression and War years - they were necessary engineering advancements, changes to bring in the modern age of steam power. And part of this key design change was in the wheels.
-------------
Ralph P. Johnson locomotive design engineer for Baldwin Locomotive Works in his book THE STEAM LOCOMOTIVE discusses the all critical engineering changes in the development of improved locomotive drive COUNTERBALANCING.
"The problem of counterbalance is still an open question. Every new locomotive cycle has been accompanied by a re-occurrence of either damaged track rails or excessive locomotive maintaince problems, the causes for which were, in most cases, traced to dificient counterbalance method...for the maximum reduction in dynamic augment every effort should be made to make the revolving and reciprocating parts as light as possible, consistent with strength requirements. Advantage should be taken of improved design and high quality alloy steels to keep the weights of these parts to a minimum.
A difficulty encountered in balancing driving wheels is the fact that there is often not sufficient room in the wheel to take the amount of lead required for proper balancing. This is particularly true where old locomotives with small wheels have been used in faster services. There are now on the market several types of disc or box section wheels which not only are stronger than the spoke type wheel but make it possible to reduce the diameter of the axle and crank pin hubs, hence lightening the upper part of the wheel and affording more space in the lower half for the lead in the counterbalance. This type of wheel also eliminates the trouble experienced from shrinkage cracks in spokes and provides equal pressure of the rim on the tire."
---------------
Continuing on the subject Ralph Johnson talks about the nature of the individual railroads themselves regarding track condition as an aspect of the engine design problem.
"The tendency in steam locomotive design has been always towards greater size and power, but today the limit in size seems to have been reached, due to the physical characteristics of the railroads. The most important of these restrictions is the roadbed which limits the total permissible weight of a locomotive. This total weight includes not only the static weight of the machine but a "Dynamic Augment" caused by the varying vertical forces which occur in the revolving driving wheels...this force tends to lift the wheel from the rail through part of a revolution and enhances the static load through the balance of the revolution.
The designer is, therefore, constantly endeavoring to minimize the dynamic augment, for it is equally injurious to the rail and to the locomotive structure...As an example of the results obtained by the use of wheel type, the case is cited of a 2-10-2 type locomotive built in 1916, with a 63-inch driving wheels, which was placed in service requiring higher speeds than the engine had been designed for. The railroad engineers found over 700 bent rails in a distance of 100 miles, occuring always at the foot of a descending grade. The kinks occured at a distance apart equal to the circumference of the 63 inch wheel, namely 16 feet 6 inches...by substituting cross balanced, disc type wheel centers on the main wheels the underbalance was reduced to 260 pounds and the rail trouble eliminated."
----------------------
Johnson also cites several railroads and the use of the greased slip track to measure engine drive wheel balance issues.
"Several railroads made slip tests with their locomotives over greased sections of track and by experiment with the amount of weight in the counterbalance arrived at a solution of the problem. These tests demonstrated that, for the same overbalance, a 'stiffer' roadbed requires a higher slipping speed to set up vertical oscillations of the main drivers than a softer track. In one case, a slipping speed of 165 mph on one test showed but slight marking on the rail, while a similalr test conductged on more resiliant track showed severe rail damage at a speed of 105 mph..."
----------------
Consider now the AT&SF 5011 class "Texas" freight engines with their massive frames, their record setting piston thrusts from 30x34 inch cylinders of 219,000 pounds which is a historic performance record. These remaining Santa Fe steam engines rank among the finest steam power ever built with their massive 74 inch Boxpok wheels, light weight rodding, roller bearing drive construction, high boiler pressure of 310 psi, oil fired furnaces - all this on such a massive scale.
Forget not also the heroic railroads built across the nation with track structure that could run such engines at speed. Consider also the economic power of the nation that needed them to run at speed also.
Yes think about them now rusting in parks and weeds - their heroic performance not forgotten by those who just couldn't bring themselves to scrap them. They deserve better treatment than they are getting by the preservation community.
Doc
Overmod, that is a sad picture indeed. But what a great locomotive! I hope somehow it ends up at either the Railroad Museum of Pennsylvania in Strasburg, PA, or the Lake Superior Transportation Museum in Duluth, MN, and not as Gillette Mach 3 razor blades.
kgbw49From what I have been able to gather, here is an example of the last 2-10-4 fleet operating in North America - Duluth, Missabe & Iron Range 2-10-4 purchased from Bessemer & Lake Erie...
Strange you should mention 'last 2-10-4' and 'Bessemer & Lake Erie'
From what I have been able to gather, here is an example of the last 2-10-4 fleet operating in North America - Duluth, Missabe & Iron Range 2-10-4s purchased from Bessemer & Lake Erie...
Of course, only on the Missabe and a few other roads could something as large as a 2-10-4 be considered "little" power...
M636CThe Japanese seem to have frozen their Boxpok designs at those used on the Milwaukee Pacifics. The C62s, "converted" from wartime D52 mikados retained this design, however the wartime standard gauge mikados, derived from a 1918 South Manchurian Alco design, had the later "small oval" Boxpok design
How had the design evolved (particularly with reference to the main-pin 'fit') by the time Mitsubishi built the last batch of 2-10-2s for Rio Turbio?
And what were the driver characteristics for the GELSA locomotives -- I never thought to look at those carefully as to source or detail design.
A recent book on ATSF steam power (my copy is 200 miles away right now so I don't have the details) provided a good background in LFM and other disc driver designs on the ATSF at least.
I will bet that this is Larry E. Brasher's Santa Fe Locomotive Development, section 15, pp.206-210. Since my copy was several orders of magnitude closer I can answer questions about it with little difficulty.
An interesting thing in ATSF nomenclature: the Baldwin Disc centers were called out as "B.L.W. disc type", and the 3776 specs (in July 1940) says "Driving wheel centers to be of box or disc type, of cast alloy steel, AAR grade C or an acceptable equivalent." By 1943, the spec was more defined, as "Boxpok type, designed by the General Steel Castings Company" -- I suspect this explains why the driver in the Chris May picture (off a contemporary 2900 class) specifically has the notation "Boxpok by Baldwin".
Reading between the lines, "Universal" was a brand name used by LFM; it applied to sectional packing first, then to cast cylinders, crossheads, lightweight pistons, and even diesel-locomotive truck frames (the one illustrated in an advertisement, though a line-art drawing, resembling that of a "Blomberg" swing-hanger B truck). Specific advantages were listed (in 1948): "The improved design, the better casting offer better tire mileage, greater resistance to power thrusts, road impact and lateral pressure. Ample hub sections permit pressing off and on the same axle without loss of required pressure fit." They also added something I had not thought about before reading about it in their advertising: the construction not only prevented 'the rim flattening between spokes in service', but also '[did] not crown in the transverse section'. A stated advantage was that 'metal sections are maintained practically uniform throughout the wheel center resulting in a better casting' - this partially explaining the very unusual sizing and contour of the openings in the driver and the form of lip around them.
It's important to remember to refer to the author Larry with the "E" as middle initial. This is out of respect for his father, middle initial "J", who among many other things was instrumental in developing the 3765 class.
The Story of disc driving wheels is indeed complex, particularly regarding application outside the USA. The Japanese seem to have frozen their Boxpok designs at those used on the Milwaukee Pacifics. The C62s, "converted" from wartime D52 mikados retained this design, however the wartime standard gauge mikados, derived from a 1918 South Manchurian Alco design, had the later "small oval" Boxpok design. The Russians also adopted the early version pre WWII, but the Lebedyanski standard post war locomotives classes L and LV, P34 and P38 all had the later small oval Boxpok, which of course was carried on to the Chinese QJ which initially was was no more than a P34 boiler on an LV chassis.
I can't think of Scullin discs without thinking of the half of the Dreyfuss Hudsons with their silver painted Scullin Discs illuminated at night. But post WWII, many of the Hudsons got replacement Boxpoks because the large areas of plain disc in the Scullin design were prone to cracking. It is possible that some early Baldwin Disc drivers were also replaced by Boxpok in the later 1940s.
The SCOA-P design was a U shaped spoke with the hollow facing outward which was incorporated into the rim. This gave better support to the tyre without large volumes of casting that could contain defects and initiate failure.
This SCOA-P design arrived post war and was only applied to a handful of locomotives, the last of which was a Queensland branch line GE A1A-A1A using the power equipment of the standard 70 ton unit.
M636C
Overmod Dr D Because of this unique high performance nature and the "one off" nature of its construction - it was the only locomotive - the ATSF 5000 was given the name MADAME QUEEN by railroad workers for its remarkable performance and undoubtedly its special roundhouse queen nature. Being the only locomotive of its type it required all the roundhouse repairs to be of a unique and special in nature. Some of that may apply, but I suspect ATSF people will confirm they called her that because of a radio-show character -- not a politically correct one by today's standard. Madam(e) Queen was a character on the Amos 'n Andy show...
Dr D Because of this unique high performance nature and the "one off" nature of its construction - it was the only locomotive - the ATSF 5000 was given the name MADAME QUEEN by railroad workers for its remarkable performance and undoubtedly its special roundhouse queen nature. Being the only locomotive of its type it required all the roundhouse repairs to be of a unique and special in nature.
Some of that may apply, but I suspect ATSF people will confirm they called her that because of a radio-show character -- not a politically correct one by today's standard. Madam(e) Queen was a character on the Amos 'n Andy show...
https://books.google.com/books?id=cXpzAQAAQBAJ&pg=PA62&lpg=PA62&dq=%22formidable+madam+queen%22&source=bl&ots=JVYm0fMLz1&sig=a2A5Qu-VSXfO7Ci5dzla3Q0yVt8&hl=en&sa=X&ved=0ahUKEwi997Cdx63NAhXIlx4KHQ42BoUQ6AEIHDAA#v=onepage&q=%22formidable%20madam%20queen%22&f=false
Gentlemen,
You have all heard of TRUMP UNIVERSITY, well I give you OVERMOD UNIVERSITy - I attend classes there regularly!
BOB WITHORNThe latest was Pennsy BUT, they showed a bunch of 5000 class ATSF locos rolling through Ohio to I think a yard in Sandusky on the Nickle Plate. Why so far east, It was in the 50's.
Oho! You don't know about PRR leasing the ATSF power for ore service on the Sandusky branch in the middle '50s! You have SUCH a treat in store...
There was a specific thread on this subject in the forum at the beginning of 2011, and you might want to read it.
http://cs.trains.com/trn/f/740/t/184628.aspx
There's lots of railfan photography, both still and movie, of 5011-class and Js working together on ore trains. Quite a bit of coverage online, too
[Dr. D in particular: do not miss the part from 8:53 through to the end. It captures the magic of proper big steam and the skill of the people that ran it very well...]
Dr DTrains Magazine ran nice story on the power pulls that TP 610 did pulling the Southern dynamometer car. Have never seen the test data though.
I recall quite a bit of the test data were described analytically in one of the articles ... for those who don't have the "Complete Collection" it is in a bundle of articles that was available free on the Web. One notable conclusion was that the effect of surge from reciprocating overbalance was clearly visible in the traces at 45mph.
It would certainly be interesting to review the detail information from some of the runs ... but I don't think it would tell us much we don't already know. The Langer (Westinghouse) balancer of 1947 was definitively intended to relieve this situation, which the Voyce Glaze method of high-speed balancing (stiff lateral truck compliance; minimal overbalance in the main, etc.) does not really address, but drawbar surge is comparatively much less important for freight service (its elimination there being useful mainly to preclude some slipping in extreme conditions).
Common locomotive drive wheel types were of course - (1) "Spoke" drive wheels done in the old school style...
Be careful not to forget that the Baldwin 'Web-Spoke' was a decidedly different and functionally much-improved 'take' on spoked drivers. This neatly solved some of the issues with ordinary spoked construction, notably the stresses in the wheelrims, while maintaining the lower inherent unsprung mass (and cost) of a spoked design.
(2) "Scullen" disc drivers which were a solid face wheel design with large circular holes - the Scullen had a very art deco solid look to them.
Repeat after me: SCULLIN. Especially if you're gonna quote it.
There are some welded driver centers that resemble the look, with much smaller holes (an example is in the K4 section of Staufer's Pennsy Power). I thought for some time when I was little that the Scullin was a fabricated, not cast driver (just as I thought that Timken lightweight rods were of light-alloy construction, a refinement of the PRR's testing of aluminum rods on Decapods and the like in the '20s) but it is most emphatically not. There is a very good explanation of the Scullin Disc center in the '47 Cyc, and I think in the '52 but I'll have to check.
(3) "Baldwin" drivers with the rounded corner shaped spoke holes and external ribs
These should always be called "Baldwin Disc" (the two words together). Some later versions do not have the 'stiffening ribs' that give such a good Art Deco touch -- I suspect these were an "aesthetic" touch rather than necessary functional reinforcement, and if so I think it succeeded admirably. ATSF 3463 has these wheels (and will probably wear them when trying to reach 130mph...) -- if you want to have fun, look at all 6 of the drivers presently on the locomotive and tell me what you note about the stiffening ribs...
(4) The great "Boxpok" fabricated drivers done by General Steel Castings which was also owned by Baldwin Locomotive Works...
HALF-owned ... this is important.
Go back and look at the recent Chris May driver photograph for a very clear indication of what Baldwin cast into Boxpok drivers it put on its locomotives.
... - these had the smooth face with egg shaped spoke holes
Don't leave out the 'big hole' Boxpok design, perhaps the most exotic of the cast driver centers, as seen on some of the early high-speed C&NW Pacific conversions and, I think, tomikawaTT's beloved Swallows. These have four large almost-circular holes in a quatrefoil arrangement
(three out of 4 here have them, including the Mike for those who think only larger power benefited from cast driver centers...)
- and finally (5)"Universal" drive wheel designs - which looked a bit like the Baldwin without the external spokes and to my knowledge were very seldom written about.
From LFM ("Locomotive Furnished Materials") which was an online customer of ATSF. Much discussion of these is comparatively recent. There is at least one ATSF 4-6-2 currently operating that has these; here's a different one that shows the 'detail difference' rather well:
Now, I do have to wonder if trying to get off the Paraquat by lacing your spliff with lysergic acid diethylamide is the right answer if this is the result:
The "Boxpoc" [sic]was of course constructed of hollow sections allowing for massive varying lead counterweights to be added to them internally - which weights couldn't be added to the other designs.
Run that by anyone who doesn't already know how a Boxpok wheel is cast and you're likely to get only confusion and delay.
There is no 'massive varying lead counterweight' in most of the box-spoke hollow sections. There are precast pockets for counterweights in the appropriate places, just as there can be in spoked drivers -- the difference is that the structure around the pocket is stronger and distributes stresses better. To my knowledge, there is nothing about the Scullin (which has the opening to its 'pocket' on the inside, for aesthetics) that would indicate 'weight couldn't be added' in the same proportions and with the same precision as in a Boxpok center, and the same would appear to follow for Baldwin Disc considering how many locomotives with them routinely exceeded 100mph with heavy trains
We expect better from you considering your history and knowledge.
(BTW, you shouldn't leave out BFB or SCOA-P here, even if they weren't used domestically...)
------------
Pardon me while I light up another blunt ...
Well, this is America. But lay off the acid, OK? Or at least stop with the 1500 mikes business -- we all like Mikados in principle but that is a bit much...
Overmod,
Damn! I hate to give up those "blunts laced with Paraquat!" - and just when I was havin' a really good time too!
---------------------------
ATSF 5001 and 5011 my bad with 74" Boxpok drivers not 70."
---------------------
I remember when Southern Railroad was using the Texas & Pacific 610 painted up as a Southern locomotive - looked better in T&P black and red! Trains Magazine ran nice story on the power pulls that TP 610 did pulling the Southern dynometer car. Have never seen the test data though.
Also some nice coments on the locomotive driver balance subject and of course the lack of such problems when resorting to Duplex Drive.
Common locomotive drive wheel types were of course - (1) "Spoke" drive wheels done in the old school style, (2) "Scullen" disc drivers which were a solid face wheel design with large circular holes - the Scullen had a very art deco solid look to them. Also (3) "Baldwin" drivers with the rounded corner shaped spoke holes and external ribs. (4) The great "Boxpok" fabricated drivers done by General Steel Castings which was also owned by Baldwin Locomotive Works - these had the smooth face with egg shaped spoke holes - and finally (5)"Universal" drive wheel designs - which looked a bit like the Baldwin without the external spokes and to my knowledge were very seldom written about.
The "Boxpoc" was of course constructed of hollow sections allowing for massive varying lead counterweights to be added to them internally - which weights couldn't be added to the other designs. This was a very unique and superior cast steel wheel design.
- Pardon me while I light up another blunt,
Kansas City Southern 2-10-4 with 70 inch drivers...
Pennsylvania 2-10-4 with 70 inch drivers...
ATSF 5001 class 2-10-4 with 74 inch drivers...
ATSF 5011 class 2-10-4 with 74 inch drivers...
Pennsylvania Q2 4-4-6-4 with 69 inch drivers...
Altoona, Toleda & Sandusky Fostoria 2-10-4 hauling black diamonds from Columbus, OH to Sandusky, OH - delivered to Columbus, OH by a Norfolk & Western 2-6-6-4...
Dr DThe problem was addressed and solved with rebuilding of the T&P 600 series engines but never satisfactorily resolved until the larger 69" drive wheels were designed for the Chesapeake & Ohio 2-10-4 design.
The situation was well-enough resolved on the 1938 rebuilding of the original T&P locomotives to suit them for any traffic T&P needed to run them. If you have not read the DPM 'dynamometer car report' done when the engine was in excursion service for the Southern, you should do so now. (Note the Boxpok main, and the reasoning behind why it is in there...) This is particularly interesting because the locomotive runs out of chassis stability (with the articulated trailing truck and all the reported problems with that arrangement on 'originally-balanced' SuperPower engines) before it reaches critical balance resonance in vertical augment.
That isn't to say that a locomotive with 69"-70" drivers isn't by far a superior locomotive. We need go no further than the NYC's experiments with 4-8-2 balancing to solve that one -- and our beloved 3001 is one of the poster children for the high-speed eight-coupled revolution (why there isn't a separate ASME page on this specific subject I do not know, other than a failure of vision)
[quote]Chesapeake & Ohio T-1 class, as well as the AT&SF 5000 "Madam Queen" and subsequent classes all had the larger 69 inch drivers and the later 5001-5011 class engines had 70 inch Box Pok drivers with very advanced driver balance and light weight alloy side rod construction. As such they were absolutely superior super power engines!
You are smoking blunts laced with Paraquat to think that ATSF had 70"-drivered 2-10-4s of any kind. One of the great sobering features of those locomotives was that they had, from the outset, 74" drivers, and angle-cross-balancing as well -- higher drivers than typical passenger power most other places, including NYC Mountains regularly run at 80mph or faster.
I would note, in passing, that the very best balanced 70"-drivered engines of all did not have Boxpok drivers -- indeed, didn't have disk drivers of any kind, or even Web-Spoke rim reinforcement. Which is not to say that some version of stronger driver center wasn't a desirable feature on a locomotive with high main-pin loading or restricted metal between the pin and axle bores -- the latter being the real 'key' determinant of stroke reduction on high-speed engines, by the way. While it is difficult to decide where the 'limit' of effective balancing size was, part of the difficulty is that true lightweight rod construction was highly expensive, especially the Timken big-eye rods with restricted lateral dimensions that required roller bearings. That in turn limited the actual weight reduction possible for rodwork on locomotives with high piston thrust, and therefore the balance weights needed to be carried without structural compromise in the wheel rims.
Sweet spot is probably at 68" (as seen on the Big Boys, with 69" being dramatically better (especially on the Q2) and 70" even more dramatically better. Arguably the distinctive 'advantage' of the 4" driver increase of the ATSF 'big three' 2-10-4 design might not have been fully reached in practical terms ... but am I glad they kept it in! (And the design is infinitely superior to piggish 5000...)
Note the particular advantage possible in driver diameter with the design specified in the ACE3000 (the article about this in Classic Trains has, in my opinion, a number of conceptual flaws). I continue to think that even a modern well-balanced locomotive benefits from reasonably large driver diameter, even when computerized balancing with exotic materials can be used. Among other things, the need to re-turn or replace wheels is less...
Let's not forget the "johnny come lately" design of the Pennsylvania Railroad who in the midst of the wartime demands of heavy traffic had to go to the 2-10-4 Texas J class engines by borrowing the Chessie blueprints.
Had they borrowed the ACTUAL Chessie blueprints, they would have had far fewer issues with those 69" drivers! That is frequently ascribed as the cause of the balance troubles, and I think that for a railroad with a hard 50-mph limit on the trains a J1 or J1a would pull, even the 'developed' stage of balance the C&O achieved through experience would be adequate. That PRR felt it useful to go to 70" drivers says more about the AMC and its understanding of practical high-power priorities than some fundamental weakness in using a 69" wheel.
I continue to think that a conjugated duplex remains a better solution for even moderately high speed (at full load, which is an essential criterion) locomotives than any practical high wheel on a straight ten-coupled engine of equal high capacity. On the other hand, there's little practical argument that as PRR used freight locomotives the J1a was nearly the functional equivalent of the Q2, with much lower maintenance expense... and both engines were functionally oversized and overpowered for most practical 'diesel competition'.
Absoluely love the Santa Fe covered wagon streamliner models - some serious Santa Fe diesel modeling here!
Kgbw49,
Regarding drive wheel diameter and its importance, if I remember right, one of the serious design problems with the first 2-10-4 Texas locomotives produced as LIMA SUPER POWER was the small drive wheel diameter built with the namesake Texas & Pacific 600 class engines. Drive wheel balance was so bad that when the engines were run too fast they kinked miles of main line track from the bad dynamic augment of the imbalance in the small drive wheels. For this reason a strict speed limit was placed on the engines.
The problem was addressed and solved with rebuilding of the T&P 600 series engines but never satisfactorily resolved until the larger 69" drive wheels were designed for the Chesapeake & Ohio 2-10-4 design.
I suspect the Canadian Pacific, Vermont Central, Burlington RR, Chicago & Northwestern, B&LE and other locomotives were also fairly low speed designs.
Chesapeake & Ohio T-1 class, as well as the AT&SF 5000 "Madam Queen" and subsequent classes all had the larger 69 inch drivers and the later 5001-5011 class engines had 74 inch Boxpok drivers with very advanced driver balance and light weight alloy side rod construction. As such they were absolutely superior super power engines!
Lets not forget the "johnney come lately" design of the Pennsylvainia Railroad who in the midst of the wartime demands of heavy traffic had to go to the 2-10-4 Texas J class engines by borrowing the Chessie blueprints. Almost direct coppies of the C&O T-1 including a non-Pennsy "radial stay" firebox the Pennsy produced an extremenly large fleet of over 125 of the 2-10-4 engines just before the end of steam! Reports are the early Pennsy "Texas" engines had drive wheel balance problems even with the 69" drivers. Pennsy also borrowed a number the ATSF 5001 and ATSF 5011 class super Texas 2-10-4 engines to run on its eastern railroad sometime in the 1950's. Sure would have been weird seeing these massive western engines burning oil and running in Appalachia coal country!
kgbw49 Madam Queen on Raton Pass...a little grainy but a great picture (any conjecture as to the diesel model?)...
Madam Queen on Raton Pass...a little grainy but a great picture (any conjecture as to the diesel model?)...
The photo is by Preston George on 19 May 1946.
The train is the Super Chief, the train locomotives are E6 type numbers 13L and 13A.
The photo appears on page 162 of J.B.McCall's "Early Diesel Daze".
Madam Queen contemporaries from 1925 to 1930...
Texas & Pacific with 63 inch drivers...
Canadian Pacific with 63 inch drivers...
Chicago, Burlington & Quincy with 64 inch drivers...
Chicago Great Western with 63 inch drivers...
Bessemer & Lake Erie with 64 inch drivers...
Central Vermont with 60 inch drivers...
Cheaseapeake & Ohio with 69 inch drivers...
Madam Queen with 69 inch drivers...
Just a few comments on the operational history of the 5000's and 2900's. Both were badly needed and heavily utilized when built. The 2900's operated between Kansas City and Los Angeles via Raton Pass on crack passenger and mail and express trains. They ran non-stop except of lineside servicing, more than 1,600 miles which was the longest run for any US steam power. The 5000's, including Madame Queen were concentrated on he Belen Cut Off running between Clovis, NM and Belen over the Abo Canyon grade. This was a major bottleneck on the Santa Fe's freight route to the West Coast and the 5000's were prized for their ability to haul the standard Santa Fe freight consist of 4000+ tons over the line quickly and without resorting to helpers. After the War, Santa Fe dieselized rapidly and both classes of engines were held in reserve to handle seasonal perishable traffic. They performed magnificently on the relatively flat territories between Clovis and Kansas City well into the 1950's.
Way cool! Thanks!
Finescale 1:48 comparison of early ATSF E units.
The radiator openings in the roof of E3s are not as visible as on the E6. Note that ATSF had only one E3 pair, so this would match the Madam Queen picture, right down to the 2 different-size horns, if that's what it is.
As a spotting feature, seems to me that the side number plate is in front of the rectangular window in the 'warbonnet' paint curve on the E3, but behind it on the E6. Someone with a magnifying glass ... or a better version of the picture ... might be able to tell.
I'm thinking E6.
The diesels in the last pic are E3s or E6s. E1s didn't have roof radiators.
The diesels are an EMC E1A/B set. AT&SF had 8 E1A and 3 E1B units. I don't think the "L" suffix was in use yet so the A/B sets were 2/2A, 3/3A and 4/4A with the others numbered 5-9. Two 900HP 201-A engines per unit. They were rebuilt into E8Ms in the early 1950s. The three A/B sets were originally assigned to transcon trains, especially the Super Chief, with the others assigned variously to Golden Gate, San Diegan and Chicago-Kansas City-Tulsa trains.
The guts of the E1 were very similar to the original Super Chief diesels 1 and 1A, the main differences being in the carbody and the trucks.
Our community is FREE to join. To participate you must either login or register for an account.