You must not have seen the fancy metalflake paint on those passenger Geeps... ;-}
Incidentally, I heard a story that the Geeps obtained in 1958 were actually part of a PRR order that was 'diverted' because of the recession. When the recession ended PRR wanted, and got their Geeps back, and N&W then had to wait to 're-dieselize' a couple of years later.
Imagine: an A with the streamlining from a J or a K2a! Something to sketch...
NW
Overmod You must not have seen the fancy metalflake paint on those passenger Geeps... ;-} Incidentally, I heard a story that the Geeps obtained in 1958 were actually part of a PRR order that was 'diverted' because of the recession. When the recession ended PRR wanted, and got their Geeps back, and N&W then had to wait to 're-dieselize' a couple of years later.
That particular order from EMD (order number 5570) resulted in a surplus of units due to the mentioned recession and a lengthy steel stike. The N&W in need of some power leased 30 units in 1958, and retained 18 of them into 1959. The temporary situation was a benefit to both roads.
But the N&W did not need to reactivate steam locomotives that had already been taken out of service.
Guys , I'm awfully sorry having to remark this thread is *not* about the financial / business relations between PRR and partly owned N&W and the consequences it had on dieselization less on how these diesels were painted or not at some times or other ...
Would you mind to rejoin the thread or put up your own one as like "How N&W diesels were painted if you can believe it and why it was not the other way we thought it should have been were it not evil Pennsy had interfered ..."
Without intending to complain , it strikes me that there are many kinds of details touched but the main question of interest and topical here doesn't seem to really light up with more deeper thoughts contributed except for short interim bursts that die down quickly to make way for little details wayside , actually ...
No insult intended
Juniatha
Hello...
I'm still interested in your three cylinder valve gear solution. Can you explain which method you would use?
Thanks,
friend611Firelock:I completely agree with your point of view. There was no point in the Powhatan Arrow remaining without the J's, as it had been conceived as a streamliner. The best thing was to either keep the J's to run the Arrow or discontinue the train, which was sadly, not done until 1969, ten years after the last J (611) was retired.Lois
Ah Lois, dear lady, you hit the nail on the head. Now maybe if they kept the J's on the train and called it a "ride" instead of "transportation", who knows what might have happened? Steam-starved railfans from all over the country would have descended on it! OK everybody I know, railroads aren't in the entertainment business, but still, it's fun to speculate on.
Wayne
Juniatha ... it strikes me that there are many kinds of details touched but the main question of interest and topical here doesn't seem to really light up with more deeper thoughts contributed except for short interim bursts that die down quickly to make way for little details wayside , actually ...
How can it be an insult if it's the truth? Maybe this time there won't be further distraction...
I do think that discussing N&W design solutions from the mid-Thirties, especially ones that were not later pursued, as if they were the 'be-all and end-all' of N&W practice, is a bit counterproductive. We very briefly got into some of the historical design details of the Y-7 without ever proposing explicit improvements on those details (which was, I thought, the point of the thread in the first place). Or noting how very preliminary some of those details were (e.g., those designed before practical experience with their counterparts on the A was obtained).
So far, nobody has commented much on the 'improvements' of the ancillary systems on steam locomotives if active development had continued past 1947. In particular, I raised the issues of combustion-air preheat and better circulation patterns in the water legs, for both of which very competent (as tested) modalities were developed. These are comparatively small changes that were reported to give large percentage gains in efficiency when used. (Note that I avoid naming the two prevalent systems being marketed -- I have discussed them before, and am tired of being accused of 'name-dropping' when referring to particular engineers and their designs... ;-} )
I believe Juniatha commented waaaaaaaay far back that the greatest 'improvements' in steam operations, in the absence of dieselization, weren't going to be thermodynamic; they were going to involve better maintenance and servicing procedures and, to an extent, systems on the locomotives that facilitated that. One example (which is actually still somewhat relevant today!) involves the replacement of total-loss lubrication on locomotives. I have so far not succeeded in finding a full reference to pressure lubrication of rods, pins, and valve gear (it was mentioned as being tried in China in the mid-Fifties). However, a combination of cross-drilling and small check valves, combined with a combination of hardlines and flexlines on the rods, easily permits positive lubrication of all the rods, and the driver-axle boxes and thrust liners, with comparative ease.
Who has an opinion on the relative benefits of the Hadfield steam reverser (Beyer-Peacock, 1950) as compared with the more conventional air-operated Franklin gear? Was it in any sense more reliable, or was it just a system optimized for use with vacuum brakes (and therefore no high-pressure air available conveniently on the locomotive)?
Ash handling on solid-fuel locomotives is (to me, at least) an interesting topic. The Brazilian GELSA locomotives used very large external ashpans; the N&W TE-1 had a row of outside-dumping doors (which caused problems compared to arrangements that dumped into pits between the rails); a number of attempts to adapt 'ashaveyor' marine systems to increase the range between required dumps were made (and more were possible). What are the opinions about the improvements in ash handling systems we would have been likely to see?
We can get into some of the advanced features of Chapelon's or Porta's designs later, because I would expect approaches like his to be characteristic of later-era steam design had it remained a field of interest. In particular, it would be interesting to see how the improvements proposed for the 2-10-4s that were to be marketed here would have been received. (The closest thing to this, imho, were the KCS "sport model" 2-10-4s that were so quickly abandoned upon dieselization; with welding making those 310-psi boilers practical, this might have been an interesting pattern.
One other point: I do NOT see 'standardization' (of the EMD, the USRA, or the 1950s British kinds) being a major part of the design evolution. On the other hand, I see an increased scope of 'modularization' beyond the usual suspects (ancillaries, drivers, roller bearings) to give lower marginal cost for both new power and improvement-project parts. There was an interesting groundswell of postwar "improvements" on (already-depreciated) older locomotives, and it's interesting what was changed, and to what, in the course of this development.
I apologize in advance if this is not the kind of Big Issue that qualifies as a 'main question of interest and topical'. But these are more important than arranging drivers novelly, or going after producing levels of single-unit power that proved either undesirable or unworkable in economically-justifiable North American service.
BTW, I am flatly surprised that Karen Parker has not taken up the issue of a streamlined passenger A with roller rods and all; someone ought to suggest it to her if she hasn't in fact done it already. And, before we quite drop the subject of the N&W and PRR, what if, indeed, the PRR had adapted the A instead of the J:
pmpennsy.htm
(I see at least one thing that probably would have been done differently on a real one; consider the combustion-chamber construction...)
Also BTW, If I haven't seen any comments on the multicylinder valve gear in a couple more days, I'll go ahead and say something myself. The application of Cossart drop-valve gear with 'salmon rods' for longitudinal balance (general layout as seen, for example on the Algerian Garratts) to large North American power is an idea that seems to have dropped without a trace, but I think it does deserve some very careful consideration...
Juniatha Guys , I'm awfully sorry having to remark this thread is *not* about the financial / business relations between PRR and partly owned N&W and the consequences it had on dieselization less on how these diesels were painted or not at some times or other ... Would you mind to rejoin the thread or put up your own one as like "How N&W diesels were painted if you can believe it and why it was not the other way we thought it should have been were it not evil Pennsy had interfered ..." Without intending to complain , it strikes me that there are many kinds of details touched but the main question of interest and topical here doesn't seem to really light up with more deeper thoughts contributed except for short interim bursts that die down quickly to make way for little details wayside , actually ... No insult intended Juniatha
How often have other threads taken a side road to make a point or educate before returning to the topic a hand? It happens and many times with good intention.
K4sPRRHow often have other threads taken a side road to make a point or educate before returning to the topic a hand? It happens and many times with good intention.
The issue is that this thread has drifted so much in the past that Juniatha had to split it into a few threads: this one and a couple Extreme Steams. So that is why we need to keep it on track or start new threads. I caused it to drift a couple pages back, and I was the one who introduced GP9s into this thread, so I am to blame this time. Sorry Juniatha, and everyone, I will try to think of better examples next time.
Sorry,
Hi Everyone,
OvermodI see an increased scope of 'modularization' beyond the usual suspects (ancillaries, drivers, roller bearings) to give lower marginal cost for both new power and improvement-project parts.
As do I. There is the old joke of "Not two alike", but only having to manufacture a couple types of rods would be cheaper then one per class.
OvermodWhat are the opinions about the improvements in ash handling systems we would have been likely to see?
I would like to see a system that conveyed it into a section of the tender, with a hopper style dump door for simultaneous fueling and ash dumping. Driven by a small engine, perhaps the booster through gearing?
OvermodAlso BTW, If I haven't seen any comments on the multicylinder valve gear in a couple more days, I'll go ahead and say something myself. The application of Cossart drop-valve gear with 'salmon rods' for longitudinal balance (general layout as seen, for example on the Algerian Garratts) to large North American power is an idea that seems to have dropped without a trace, but I think it does deserve some very careful consideration...
Please tell us about this!
Thank you for the link,
NorthWest OvermodWhat are the opinions about the improvements in ash handling systems we would have been likely to see? I would like to see a system that conveyed it into a section of the tender, with a hopper style dump door for simultaneous fueling and ash dumping. Driven by a small engine, perhaps the booster through gearing?
I think my preference would still be to drive it via the Lewty system (which was originally developed to make booster construction better). This uses a small triple-expansion engine, mounted in a 'thermodynamically optimal location', which drives a hydraulic pump. The locomotive ancillaries are then driven via 'fluid power' with simple hydraulic actuators or motors, of lighter weight, greater sealing ease, etc. It is not difficult to provide hydraulic accumulation to provide quicker actuation, decrease cycling time for the engine, etc.
Since ash handling is a high-temperature, abrasive, corrosive environment, I think it makes sense to have a minimum of complex machinery in that location. While it would be possible to put a Lewty engine and pump at the rear of the locomotive -- in the general location of the present stoker drive whether on the engine or in the tender being one reasonable alternative -- I think it is better to find a location similar to where Porta proposed.
I don't know if the Lewty or Porta systems were developed so far as to specify the characteristics of the hydraulic fluid that would be used. But there are certainly modern products that fulfil the requirements, and given the relatively small volume and potentially long lifetime involved, these should be cost-effective in this service.
It is fun to speculate on the effective design of the 'booster' driven by a Lewty arrangement, but I will not go into that here... ;-}
OvermodAlso BTW, If I haven't seen any comments on the multicylinder valve gear in a couple more days, I'll go ahead and say something myself. The application of Cossart drop-valve gear with 'salmon rods' for longitudinal balance (general layout as seen, for example on the Algerian Garratts) to large North American power is an idea that seems to have dropped without a trace, but I think it does deserve some very careful consideration... Please tell us about this!
I do not have a drawing of the arrangement that I can conveniently post in this thread, but it is covered in French-language references which I can e-mail on request.
Some people separate the valve drive of the Cossart system from the actual valve arrangement at the cylinder block. I will adopt that approach here, because the 'salmon rod' arrangement does not require the use of the Cossart drop-valve arrangement to work properly.
Look at this picture of the Algerian Garratts for reference.
The 'eccentric crank' carries a heavy, forward-weighted rod that is 180 degrees out of phase with the connecting/main rod. (This usually contains large 'lightening' holes, so do not be fooled by what you see here!). The forward end of this rod engages an oscillating lever, the top of which moves a similar-length rod (note how it is constructed with lightening holes and increasing section width toward the center, following the moment diagram for a beam) that drives the crank at the cylinder block.
The accepted wisdom is that this crank rotates, rather than oscillates, so it re-creates the motion of the eccentric crank circle up at the cylinder block. Note that in this version, it is providing valve drive but not timing. On the other hand, the mass of the salmon rod effectively counteracts that of the longitudinal component of main rod, crosshead, piston rod and piston, etc., and is always in proper 180-degree phase from it (like the action in a Shaw four-cylinder locomotive). This eliminates any need to put reciprocating balance in the wheels (where it does not belong).
Cossart expressly points out that if the motion of this shaft is reduced at the actual camshaft to 2:1, the same cam can be used for either end of the cylinder. Phasing of course is no longer critical, as the motion of the cams is derived from gearing and not geometric arrangement of the rods, so there is no need for something like the Berry Accelerator Gear.
The Cossart drop valves are interesting, to begin with because they are vertical, not horizontal. These are relatively small valves, and there is a separate intake and exhaust valve at each end of each cylinder. These look at first glance like poppet valves, and share some of the benefits of poppet valves, but they are NOT double-beat valves that are difficult to seal simultaneously on both seats, they are little piston valves in the sense that they have sliding circumferential seals, and they can be moving at considerable velocity at the moment they open or close to steam or exhaust (compare long-lap long-travel valves in conventional reciprocating steam practice). Notice that the transfer ports can be coaxial with the piston, rather than orthogonal as in conventional piston-valve (and most poppet-valve) designs.
K4sPRR Juniatha Guys , I'm awfully sorry having to remark this thread is *not* about the financial / business relations between PRR and partly owned N&W and the consequences it had on dieselization less on how these diesels were painted or not at some times or other ... Would you mind to rejoin the thread or put up your own one as like "How N&W diesels were painted if you can believe it and why it was not the other way we thought it should have been were it not evil Pennsy had interfered ..." Without intending to complain , it strikes me that there are many kinds of details touched but the main question of interest and topical here doesn't seem to really light up with more deeper thoughts contributed except for short interim bursts that die down quickly to make way for little details wayside , actually ... No insult intended Juniatha How often have other threads taken a side road to make a point or educate before returning to the topic a hand? It happens and many times with good intention.
Far too often to maintain the strain on Juniatha's good humour and patience. I believe that is her point, and her pointed request.
Crandell
selector K4sPRR Juniatha ... it strikes me that there are many kinds of details touched but the main question of interest and topical here doesn't seem to really light up with more deeper thoughts contributed except for short interim bursts that die down quickly to make way for little details wayside , actually ... How often have other threads taken a side road to make a point or educate before returning to the topic a hand? It happens and many times with good intention. Far too often to maintain the strain on Juniatha's good humour and patience. I believe that is her point, and her pointed request.
K4sPRR Juniatha ... it strikes me that there are many kinds of details touched but the main question of interest and topical here doesn't seem to really light up with more deeper thoughts contributed except for short interim bursts that die down quickly to make way for little details wayside , actually ... How often have other threads taken a side road to make a point or educate before returning to the topic a hand? It happens and many times with good intention.
... it strikes me that there are many kinds of details touched but the main question of interest and topical here doesn't seem to really light up with more deeper thoughts contributed except for short interim bursts that die down quickly to make way for little details wayside , actually ...
And a VERY valid point it is. While thread drift in some circumstances may be enlightening, it is inappropriate when the title of a thread specifically references the topic being addressed. It is particularly inappropriate when the thread is the second or third 'restart' of a topic that has drifted beyond all recognition. (And I speak as one of the guilty, so I wear the tar and feathers for this with more than usual sackcloth and ashes...)
Rule on steam_tech (not always observed, but it's a principle) is that if you want to discuss a different subject, start a different thread. That is what should have happened as soon as the N&W discussion veered off the streamlined A class, for example. If a subject is interesting enough, it merits its own thread. If it is not interesting enough, it still merits its own thread, which can then die without turning people off from thel point of the original thread, or confusing the original thread's new readers.
You may be unaware of it, but Juniatha has asked several times on several similar or precursor threads that those who participate overtly do so with more than a passing effort at sticking to the topic ... All she is asking for is a little more courtesy. I can't think of a good reason to deny her....can you?
Please, everyone, listen.
I am the guiltiest here. I brought the diesels in to explain why I think the N&W would not have built a streamlined J2, without realizing the drift potential. So I am the cause of the drift. I have expressed my regret for doing this before, and wish to do it again. Juniatha, I am sorry for the drift. We have had many excursions off of her original topic, and I know I have created at least a few. So, please, lets stay on topic. I will do my best.
Sincerely,
NorthWest
Crandell ,
now I'd really like to see where my sentences are of worse English than some of those who don't even distinguish between 'their' and 'there' or write 'ancillaries' when meaning 'auxiliaries' , spare me to name more examples , they abound !
I have seen enough quite mindboggling grammar here and never commented on it , just tried to find out what the writer meant to convey - not try to misunderstand reasonable sentences as best possible .
Introducing relaunch of this present thread I wrote >> The original thread was looking for what had been in the development line of the three major American builders in 1949 - along the lines steam had developed so far . << ending with my request for >> What further classes of ( conventional , i.e. in line with development so far ) steam locomotive could - realistically - have been expected to appear from the three builders had steam development been continued post 1949 .. to , say , some ten more years ? <<
In which way was my defining of 'steam we haven't seen' as quoted above supposedly imprecise , unclear or cryptic as some sentences I have read here and elsewhere by some who seem to always know what’s wrong with what other users write , yet are never able to present a better proposal ( other than mentioning the name of an engineer or inventor , mostly without any descriptive note on the device or machinery , less giving any explanation of it or reason why it should be recommendable or preferable ) and sometimes even indulge in trivial grinding of grammar instead of topical technical points ?
There was that absolutely superfluous and off-off-topic issue about my allegedly wrong form of plural for the term ‘duplex’ . I was informed that ‘the only correct plural in English’ was supposed to be ‘duplexes’ – something that doesn’t just sound awful but is completely off the mark since this is *not* an English word but *Latin* and , clearly , in Latin English plural rules do not apply – never did since Latin is older than modern ( US- ) English . In pointing that out , the self-appointed Grammar teacher did even carry it one step further by enlarging on supposedly correct – really incorrect – forms of plural forms that never were intended to suit the ( modern ) use of the word as a designation for a concept of a locomotive , that is : the word is being used as a *noun* - not as a verb or adverb as in the forms offered by the self-appointed teacher – a bad thing to overlook if you want to teach somebody !
Btw , here are three links to sites used with that teaching ‘wisdom’ :
http://www.frag-caesar.de/lateinwoerterbuch/duplici-uebersetzung.html
http://www.frag-caesar.de/lateinwoerterbuch/duplex-uebersetzung.html
http://www.latein24.de/latein_grammatik.htm
It will not be difficult to note all these declinations concern adjectives or verbs , not nouns . If you scroll down on the third site linked here , you will however see a practical example for plural ending ‘-i’ as I have used it , here for ‘passiva’ – ‘passivi’. It is easy to see the logic in it and conclude for ‘duplex’ the plural to be ‘duplexi’ . Also , it will be noted the two forms proposed to ‘correct’ my writing are *not* to be found !
However – surprise – one of the forms of plural I have suggested can be found here , namely with a double-ii ending , as ‘-ii’ . It *could* be discussed – alas , please by persons with an accordingly substantial knowledge of the Latin language – which one of those two is correct or if both are possible stemming from different times then under which conditions they should be used . Yet , we will *not* dive into that special field , for engineers use of terms it suffices well to use either one form of plural '-i' or '-ii' in order to let anyone who cares know what’s meant – namely , several locomotives of this concept , as in contrast to ‘doublings’ or in fact ‘copies’ of any non-described objects .
See here :
and here on last page of #24 LP :
[ beware of sarcasm on ] Now , has Brian Reed also been befallen of some lack of handling the English language and have those who are so over-critical with my use of language duly written to the publication about this incredible lapse that threatened to wipe out everything the booklet may or may not contain about these double-bouble dubious dupes Duplexications of what-ever ? It made this # of LocoProfile downright unsellable and ruined those who dared to buy it in spite of that glaring slap in the face of every upright knight and defender of righteous English , fighting all nite long 4 U ! [ beware of sarcasm off ]
It *could* be discussed – alas , please by persons with an accordingly substantial knowledge of the Latin language – which one of those two plural endings '-i' or '-ii' is correct or if both are possible stemming from different times and if so in which cases they would be correctly used . Yet we will *not* dive into that special field , for engineers' use of terms it suffices well to use either one form of plural in order to let anyone who cares know what’s meant – namely , several locomotives of this concept , as in contrast to ‘doublings’ or in fact ‘copies’ of any non-described objects .
Oh , btw , originally I wanted to comment on three cylinder valve gear and some points in recent postings - however considering these 'rectification contributions' I think I'd rather spare you the nuissance of reading it .
Regards
= J =
Hi , NorthWest
>> I am the guiltiest here.<<
No , you are not - certainly not .
Sincerely
>> How often have other threads taken a side road to make a point or educate before returning to the topic a hand? <<
Do we really have to count beans before returning to subject and then only if and when the beans are more than a number by one user ?
>> It happens and many times with good intention.<<
Well , I'd hope so at least !
Thank you for sharing these intriguing - uhm - scintillations *g*
JuniathaThere was that absolutely superfluous and off-off-topic issue about my allegedly wrong form of plural for the term ‘duplex’ .
E pur si muove. Publication is not demonstration of correctness. Making fun of Fowler does not dismiss him merely because it suits your ego. I have six years of Latin and no need to consult Wikipedia references on the subject as my sole justification. Period. End of diversion (I hope).
"Ancillaries" is a well-understood engineering term for devices that serve (the term, for those unfamiliar with Latin, derives from ancilla, maid) peripherally to the primary purpose of a machine or system. As, for example, the hydroboost pump or air-conditioning compressor on an automobile. It is certainly possible to use the term 'auxiliaries' (meaning devices that assist or help the primary function) for that functionality if you want, and in fact I would welcome establishing this distinction between the two terms here. It is, however, not objectively wrong to choose one exclusively over the other in the general context of this kind of discussion, far less is it a subject for sarcasm. End of that diversion, I hope.
Let's get the subject back on the original topic ... don't spare us the nuissance of reading your comments, as they are... at least, the ones concerning steam design are... the most important part of this thread.
One thing that needs to be made clear, however, is this: Are we merely discussing new wheel arrangements and the like, or are we also discussing the detail and systems improvements that would have been seen in the period under discussion? Since I for one, and hopefully everyone else reading this, has 'taken the pledge' not to raise further contention (aside from legitimate disagreement on the facts) there should be no further drift, and I'd like to think no further discord ... but we should clearly define what's 'in and out of the spectrum' for discussion. If it's locomotive types, fine. If it's the wider context in which those locomotive types would operate, fine too. It's not my place to define or delimit someone else's topic -- just to ask for more specificity to be certain what is intended.
I believe Firelock asked where would the N&W have gone with steam in the next decade (1960's?) if they continued with steam. I don't think the issue was how many drivers, size, etc. If steam were still around the technology of today with metal, mechanical technology and the purity of manufacturing, steam locomotives would have been built much better than back in the day. Similar to the improvements seen in automobile manufacture.
I had relatives who worked at the Juniata Shops and I was fortunate enough to have some live long enough to talk this nosey little kid about his passion of trains. They, along with other accounts of steam I have read or discussed related the frustration of how much of steams enery was wasted. One account I read said that 97% of steams energy flew out the stack. I am sure many of you read of this frustration with locomotive design people trying to invent ways to harness this energy, use it more efficiently and improve on a locotives overall efficiency. Didn't happen, ideas fail but other things did (avoiding off topic) and so the" progress of the progression" of steam halted. Today we can only theorize and state a bunch of smart stuff usually found in algebra class between all those parenthesis.
As steam came to an end railroads were discovering that bigger was not always better and that bigger in some instances created more problems with things such as the physical plant. Had the steam hold outs, the N&W, PRR, and a few others continued on I think technology would have improved the ability and efficiency of exisiting successful locomotives such as an 8 wheeler. The experimenting with turbine, steam electrics and such that the N&W, PRR, C&O and UP were doing would have continued, but it came to a halt, that off topic guy came around using some oil product.
Personally, if the steam technology were to continue the N&W would have been one of the leaders that all would have watched and maybe followed. But the inprovement in the efficient harnessing and effective usage of the steam created I feel would have been a priority for things to contine. Once this was accomplished many of the other things I read when on topic in this thread may have had some sucess. Meaning, the boiler would have to see some drastic design changes, and who knows may have resutled in a steam locomotive looking more like a GP9 (oops).
Overmod, well put!
Hello Juniatha!
JuniathaOh , btw , originally I wanted to comment on three cylinder valve gear and some points in recent postings - however considering these 'rectification contributions' I think I'd rather spare you the nuissance of reading it .
I'm still interested. The issue with the Gresley conjugated valve gear's third cylinder cutoff would be the biggest barrier to further North American three cylinder steam. While the high speed wearing of the middle cylinder (that disabled Mallard on her record run) wouldn't have been as critical in North America, having a pretty inaccessible middle cylinder need maintenance more than the others would be unacceptable.
The UP's solution of putting roller bearings IIRC did ease maintenance but did not fix the cutoff issues. The second solution of a "double Walschaerts" gear seemed to fix most of the problems. I am interested in what method you would use.
The LNER's solution of decreasing inner cylinder diameter is also interesting to consider, but it didn't seem to fix the problems on the Great Northern when she was converted to a A1/1.
NorthWest The issue with the Gresley conjugated valve gear's third cylinder cutoff would be the biggest barrier to further North American three cylinder steam. While the high speed wearing of the middle cylinder (that disabled Mallard on her record run) wouldn't have been as critical in North America, having a pretty inaccessible middle cylinder need maintenance more than the others would be unacceptable.
The issue with the Gresley conjugated valve gear's third cylinder cutoff would be the biggest barrier to further North American three cylinder steam. While the high speed wearing of the middle cylinder (that disabled Mallard on her record run) wouldn't have been as critical in North America, having a pretty inaccessible middle cylinder need maintenance more than the others would be unacceptable.
It wasn't wear on the inside cylinder that caused Mallard's problem, it was damage to the inside big end (admittedly that was a poor detail design).
The inertia loading in a lever conjugation gear, at American scale, is likely to produce enough deflection to show the problems... at high cyclic rpm. To SOME extent this can be overcome with the Australian-style rack-and-pinion versions of conjugation gear, but only if the shafts are made very stiff to limit torque whip.
The UP's solution of putting roller bearings IIRC did ease maintenance but did not fix the cutoff issues. The second solution of a "double Walschaerts" gear seemed to fix most of the problems.
But at substantially increased locomotive weight, and maintenance complexity. Juniatha has already addressed several approaches to this (as early as 2006, IIRC). I will not repeat my points about using roller bearings on lever ends or other partial-arc applications.
The catch with most forms of multiple Walschaerts/Heusinger is that it is difficult to get the 'action' forward to a middle valve cylinder facing exclusively forward -- one of the points of the Gresley gear.
That is often the fate of that kind of kludge. Decreasing the cylinder diameter [especially for the purpose nominally intended] is almost completely wrong; the solution to the hot-big-end issue (as noted elsewhere) was to get a better big end design. Or better compression control, but that is a different story.
Turning to the original question: I would reference the layout used for the 242 A1 as something to consider in a three-cylinder design, if you must have one. Of course that is optimized for Chapelon's compounding (and high French standards of maintenance).
I'm not much of a fan of three-cylinder simples, but that is only a preference, and I will not continue it here other than to note that I think sliding-cam rotary drive is a very good option... if you can use cams in the first place.
As usual , Overmod has had an overwhelming mode to step in and answer the question for me before I even had a chance to read the question - and so be it .
My God, that Algerian Garrett has got to be one of the ugliest things I've ever seen! No wonder De Gaulle pulled the French out of Algeria in 1958! Mon dieu and sacre' bleu!
Oh, hi Juniatha! It's me again!
Listen, I don't know if this comes under "Extreme Steam" but I was perusing my copy of Ron Zeils "Twilight of World Steam" and in the Bulgarian section there's a photo of a 2-12-4T. I thought Union Pacific was the only 'road that tried a 12-coupled design. Do you know anything about this one?
Oh, and everyone, I'm not going to get into a discussion of Latin. The only Latin I know is Pope Francis' phone number. Ecum-Spiri-Two-Two-0.
Don't take offense anyone, I'm Catholic as well, although if you look up the definition of "Good Catholic" in the dictionary you're not likely to find my picture there.
Sorry, didn't mean to drift the thread, but I think if the thread takes on the trajectory of a pin-ball from time to time that's a good thing, it means there's a lively discussion going on.
Firelock76 Listen, I don't know if this comes under "Extreme Steam" but I was perusing my copy of Ron Zeils "Twilight of World Steam" and in the Bulgarian section there's a photo of a 2-12-4T. I thought Union Pacific was the only 'road that tried a 12-coupled design. Do you know anything about this one?
It's probably safe to say that that the UP was the only road to have production quantities of 12 coupled locomotives. The Russians made a one-off of a 14 coupled locomotive, not sure if it was for sound technical reasons or for bragging rights.
Erik,
Based on photos and descriptions, I believe that it was mostly a Soviet Union propaganda tool. It derailed on curves, was too heavy for the track, broke couplers with its power, and was too big for turntables. It being the longest wheelbase in the world at the time (until surpassed by the PRR S1) also seems to support the publicity tool theory. (That I suspect was also much of the reason the S-1 was built).
Firelock
Regarding X-12-Xs, IIRC an 0-12-0 was built for the Philadelphia and Reading.
Also, in Germany the Wüttemberg Class Ks were 2-12-0s
Juniatha As usual , Overmod has had an overwhelming mode to step in and answer the question for me before I even had a chance to read the question - and so be it.
As usual , Overmod has had an overwhelming mode to step in and answer the question for me before I even had a chance to read the question - and so be it.
Not an 'answer', just some comments on a post in the thread. Please don't let that stop you from providing the answer, since you are evidently so inclined after all.
Oh, and guys, it's drifting again. I did not put the Algerian Garratt in there for anything other than an illustration of Cossart gear ... and discussions of European 12-coupled engines, while fascinating in their place, have little if anything to do with the topic of this thread...
Overmod, please think twice before you put a picture of an ugly monster like that Algerian Garrett on the Forum again! I passed half a glass of Coca-Cola through my nose when I saw the picture of that horror! Think that was fun? Think again!
Maybe it serves me right for muli-tasking. Eating a pizza, drinking Coke, and doing the Forum all at once.
Okay, to get back on track...
Juniatha, about your 2-12-6 and 4-10-6, what would you use to get them around the curves?
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