Hi Quentin
V8 - well , numerically , yes . However they were four separate V2 engines - and yet again you are right in that these were double action two stroke engines - that makes as many power strokes per revolution as in a gasoline V8 four stroke engine - *g* - however in that way any two cylinder SE steam engine was equivalent to a gasoline V8 engine , and if you think of their low rpm torque abilities there is something in that comparison that can't be denied .
A friend of mine many years ago had developed a concept for a V6 steam motor double bogie shunting and secondary line all purpose tank engine that was to drive axles the way geared diesel locos do . The V6 engine was to be hung underneath main frame beams between bogies , it had a particularly smooth torque profile which in connection with drive shaft and bevel gear coupling of driven axles provided for high adhesion factor ( defined as limit of adhesion on rails - not to be mixed with traditional steam 'factor of adhesion' which was defined as quotient of given adhesion mass by cylinder tractive effort , disregarding actual adhesion conditions on rail ) The concept allowed for a steam locomotive of widely adapting versatile performance parameters with diesel competitive starting tractiv effort .
Regards
Juniatha
Juniatha,
That's starting to sound like a cross between the Shay and Heisler designs, using three cylinders per side as the Shay (though the Shay only had them on one side) with the cylinders in Vee formation as the Heisler. The torque from the V-6 would have been smoother than the torque from the Heisler's V-2, so we would expect some improvement in adhesion. My understanding was that Shay's generally had a higher tractive effort than early diesel switchers of equivalent weight.
I seem to recall that Doug Self's "Loco Locomotives" website had some variations on the multiple Vee type steamers.
- Erik
....Hi = J = :
Just a question / comment...When I first saw this proto design several years ago I suppose I was fascinated with something so different.
Then...finally finding actual prints and photos of the arrangements of the "V" engines on the ends of each axle, It really caught my interest.
Now, I'm wondering how "slippery" that configuration might have been, especially in starting a load. Drive axles not connected....{Believe I'm correct on that}, it seems each axle would have spun easier than when all four would have been connected...Or am I remembering it wrong...
I briefly tried to find a photo of the "V" cyl. arrangement up close today, as I've seen in the past, but the short time I searched, I didn't come up with any, but I know it's out there.
Anyway....I think this was a fascinating experiment, and it was happening back 70 plus years ago.....Interesting.
Quentin
Well , that's pretty much what I wrote before - it was Duplex one step further - both in smooth running and in slipperiness . It sems however they were able to tackle that problem or were just about managing it when it all came to stop because of war . Slipperiness in an engine of individually powered - non-coupled - axles is a question of (a) keeping mass on axles even and balanced at all times and (b) providing for good sanding to secure a certain minimum of adhesion factor on rails (c) keeping axle boxes well aligned and free of play and geometry of wheel tires within decent limits . With PRR T1 engines slipping preferredly their first set of drivers I wonder if it didn't create differences in tire profiles first to second set which would have ever more encouraged premature slipping of leading engine .
= J =
Hi Erik
Oh , yes - it was in a way a refinement of the Heisler - not so much the Shay in that the Shay had engine unit and drive shafts outsides including sliding elements . In the V6 C-C design power bogie tank engine , drive was fully derived from contemporary diesel-hydraulic engines minus torque converter minus gear speeds . The steam motor itself was also much looking like a diesel in that it was fully closed and had intake and exhaust lines much like a combustion engine - only that it's inner secrets would have worked substantially different with a whole different valve gear , too . I don't remember if the motor was to be reversible , though , or if change of direction was to be by reverse gear . The effect was that of a unique engine , looking from lower to upper starting much like a diesel-hydraulic C-C unit , then having side tanks full length and above them a conventional steam loco boiler , cab and rearward fuel tank . Surprisingly , it all combined in pretty agreeing ways and produced a stunning yet harmoniously looking little engine . Even if I would , I needn't even ask , the guy would not want to see a technical drawing of his posted - the 'Make a Flame' picture , see 'Chally to the Nines' thread page nine - was about as far as I got with my encouraging .
I have a mental picture of the frame from the 1961 K-M units for the Espee and D&RGW with what I think a DB tank engine would look like. A bit different than a Pacific Coast Shay to say the least.
It wouldn't be too difficult modifying a V type gas or diesel engine to work as the proposed steam engine, though probably not the optimal solution. The camshaft drive would need to be modified to open/close valves once per crankshaft revolution as opposed to every other crankshaft revolution, which would allow for the steam to be supplied via the intake manifold and exhausted through the exhaust manifold. I kind of doubt that the standard intake valve could hold off much steam pressure...
Hmmm, another possibility would be using a steam turbine driving through a multi-speed planetary transmission. This would be a larger scale version of what was proposed for gas turbine cars, the power turbine would be connected directly to the planetary gearset of an automatic transmission, with the turbine taking place of the torque converter.
Just adding a few pictures of Reichsbahn class 19.10 "steam motor" loco, to visualize what we are talking about:
In 1943, she already looked sad:
Bah, visually another inverted bathtub. No match for a J, I-5, Daylight, or T. -or CP Royal Hudson
The bautfiul Daylight evening photo is marred by one item: The loco has a flat pilot/cowcatcher. I don't think all SP 4-8-4's had this type and those with more pointed ones were esthetically better in my opinion.
>> It wouldn't be too difficult modifying a V type gas or diesel engine to work as the proposed steam engine <<
I'm afraid that very much depends on what you might consider >> difficult << if you mind the regular concept steam engine worked in double acting mode , i e produced power both sides of pistons going out and in while combustion engines usually only produce power on down stroke with pressure on topside of pistons - except for slow runnng very large ships diesel engines which also have piston shafts and crossheads as a steam engine .
Because of that I'd find it hard to see how even the raw motor block could be used , not to speak of valve actuation having to be desmodromic since in contrast to combustion engines highest pressure is in the intake duct system , while in combustion engines it is within cylinder space during power stroke which serves to seal valves additionally to spring load .
You could do away with the double action feature , using a single action concept and double the number of cylinders in compensation - we would be talking of a V12 steam motor then .
Mind also , mean pressure in a steam engine , or motor in this instance , was several times lower than mean pressure during ( hot ) power stroke in both a diesel or gasoline engine - which again is one reason why steam engines ( or motors ) had very low outputs per unit of piston swept volume , with the best historic loco types reaching some 12 ihp / ltr of piston swept volume while more modest designs 'easily' failed to reach half that figure ! This contrasts with about 35 - 50 ihp / ltr in typical 1960s gasoline V8 engines , 70 - 90 in modern diesel , 80 - 120 ihp / ltr in present day gasoline engines , to name but typical rule of thumb values . Low specific output of the steam engine demanded high piston swept volumes to attain demanded power and that again - while having an advantageous effect on starting tractive effort - was largely responsible for the other drawback of the steam engine : low rpm working range , typically like 6 - 9 % of rpm speeds of contemporary gas and diesel engines . Now , if on top of that you wanted to use very short cut-offs for improved efficiency in a steam motor , mean pressure would tend to become lower again and you would quickly end up with a motor block although fairly reminiscent of a combustion engine having quite collossal proportions in relation to a diesel of equivalent output - that's probably why in his concept he hung the steam motor underneath frame beams , instead of setting it on top of them between boiler and frames - accessibility would also have been severely hampered there - while for overhaul the underslung motor could be made detachable in a bay equivalent to the one used for dropping a wheel set , the locomotive in exchange receiving an overhauled motor from shelve stocks within a matter of hours .
As for using a steam turbine , that would change the whole picture since in contrast to a steam piston engine the steam turbine is weak in torque from standstill start and high in steam consumption at the same time , thus in my view unsuited by principle for interrmittend hard push / pull working followed by coasting as typical with shunting or for widely varying loads and running speeds as required for rapid acceleration of commuter trains and mixed traffic secondary lines working .
Thanx for showing the photos ,
Sir Madog
- I think they show the concept of the V2 motors pretty well . The idea of hinging them outsides was of course to continue a good thing found in the two cylinder SE engine .
Dave ,
while you rightly remind us of topic , of which we tend to meander a bit off topic , in this engine it's really just the steam motors interest focusses on . The streamlining was sort of standardized DR design , also - if much later - called 'Stahlhelm' since it was considered reminding of a WW-II soldiers steel helmet - not exactly a compliment for a streamliner and not intended to be one by the sharp tongued critics . As for me I believe it's well known I prefer steam in plain and honest 'work cloths' , i e with streamlining kept decent and functional , advancing actual engine lines by smoothness and elegance , not too much of fancy shrowding it in non-functional voluptuous or pretentious sheet metal applications . I will apply these criteria to some engines - you may apply them to others as you prefer , no problem .
Wow....Madog added a nice group of those photos I have been scanning for recently. I had some of them several years ago, but they escaped me this go around. Thanks.
Beautiful shots of the mechanical prototype arrangement to power this engine. I think it's really sad it was distroyed here in the States back in '52. What a museum piece it would be if it was here now.
As for the design of the sheet metal, all that I've read seem to indicate the main thrust of that design was intended to allow the speed they were trying to accomplish. Seems to have worked as they did do "speed" with it on tests.
Bathtub or not....it seemed to enable it to cut thru the atmosphere. I too think there were many more "beautiful" machines in this catigory, but for what this one was intended for, perhaps the "design" was successful.
Still all aspects of it has been a major interest to me in reading, learning of the unusual engineering direction it was using. I have no facts, but the design had no rotating heavy side rods to work out the balance for....Pounding of the track, etc.....
daveklepper Bah, visually another inverted bathtub. No match for a J, I-5, Daylight, or T. -or CP Royal Hudson The bautfiul Daylight evening photo is marred by one item: The loco has a flat pilot/cowcatcher. I don't think all SP 4-8-4's had this type and those with more pointed ones were esthetically better in my opinion.
Not much different or worse from this one:
I have to agree to you, however. I am not really fond of those streamlined steamers.
Juniatha ...Yet , the N&W J class had a substantially higher t e per unit of engine mass on powered wheels than the K4s , in other words a lower adhesion factor , an absolute low one in relation to average US practice , which meant : no full throttle full gear starting with this engine... Regards Juniatha
...Yet , the N&W J class had a substantially higher t e per unit of engine mass on powered wheels than the K4s , in other words a lower adhesion factor , an absolute low one in relation to average US practice , which meant : no full throttle full gear starting with this engine...
This is a great point that many of you are forgetting about the N&W J Class. It also applies to the N&W A for that matter. Was the J a very good design? Yes, without a doubt. Was it the best 4-8-4 for the N&W? Perhaps, as that question really can not be answered with out a extensive test of every 4-8-4 design out there. Even if one assumes that the J design was the absolute best for the N&W's operating profile, does that mean by default that it was the best 4-8-4 design for every railroad? Absolutely not. A design that was operationally and economically good for the N&W, very well may have been an operational and economic disaster for another railroad with vastly different operating conditions.
There were many very good steam designs out there, but there was never one "best" design that would work equally well for all railroads.
Juniatha Hi Erik >> It wouldn't be too difficult modifying a V type gas or diesel engine to work as the proposed steam engine << I'm afraid that very much depends on what you might consider >> difficult << if you mind the regular concept steam engine worked in double acting mode , i e produced power both sides of pistons going out and in while combustion engines usually only produce power on down stroke with pressure on topside of pistons - except for slow runnng very large ships diesel engines which also have piston shafts and crossheads as a steam engine . Because of that I'd find it hard to see how even the raw motor block could be used , not to speak of valve actuation having to be desmodromic since in contrast to combustion engines highest pressure is in the intake duct system , while in combustion engines it is within cylinder space during power stroke which serves to seal valves additionally to spring load . You could do away with the double action feature , using a single action concept and double the number of cylinders in compensation - we would be talking of a V12 steam motor then .
That's pretty much what I was intending - the only internal combustion engines suitable for conversion to double acting steam would be double acting diesel engines. Also note that I didn't think such a conversion would be optimal, as per your comments on mean equivalent pressure.
There would be a "simple" modification to make the intake poppet valve work. The valve seat would be on the outside of the cylinder head, with the valve opening away from the piston. Assuming pushrods and rocker arms, the pivot point for the rocker arm placed on the far side of the valve from the pushrod - so the valve goes up instead of down when the pushrod goes up.
Note I said coupled to a multiple speed transmission, e.g. the part of an automatic transmission after the torque converter. One report on the Baldwin S-2 showed that the steam rate (in lbs/hr) for a given tractive effort was almost constant for speeds between 0 and 60 MPH. While the gearing would greatly improve the low speed efficiency, it still would suffer if the locomotive spent most of its time at crawling speeds.
Per GP-40's comment about there not being a "one size fits all" 4-8-4, well certainly not. A NYC "Niagara" intended for the "Water Level Route" probably wouldn't have worked at all for the PRR, neither would a 4-8-4 used by the RF&P on its fairly level track profile aand short run from Richmond to Washington. HOWEVER, a 4-8-4 designed to handle mountains and the concurrant up-and-down track profile like the Class "J" of the N&W, or an FEF-3 used by the UP which was also intended for pulling power up hills would probably served very well indeed. In fact, the UP didn't find out how good the FEF-3 really was until they were downgraded from passenger to freight service and performed outstandingly.
At any rate it doesn't matter, diesels were coming and nothing was going to stop them. I suspect most of the roads that held onto steam for as long as they did did so for reasons that made sense at the time. Steam servicing facilities were already built and were long since paid for, if the road hauled coal it usually burned it as well and was probably getting a deep discount for it.
the N&W J class had a substantially higher t e per unit of engine mass on powered wheels than the K4s , in other words a lower adhesion factor , an absolute low one in relation to average US practice , which meant : no full throttle full gear starting with this engine
But then it didn't have full gear capability. Many modern steam locos were designed with limited cut-off.
Juniatha,As for the "no full gear starting with this engine". Even with its somewhat lower figure on the "adhesion" scale, the J, unlike the T1, has never been regarded as a slippery engine. Also, discussions on other forums and other threads have tried to dispell this rumor about the T1 (Feltonhill being one champion of this campaign).
Considering that you have never operated the J or T1, that is a statement that I feel you are unqualified to make. Still, all of this is beyond the scope of this thread and should be "chiseled" out somewhere else.
.
Your comments on T1 contouring ?
Definately not a "Shark Nose". More like a "Chisel Nose" and even more like a "U-Boat" or I should say even more like a U.S. "WWII Fleet Sub".
PS Maybe someone can tell me why the font went to small and I'll fix it so a normal person can read these without a magnifying glass.
Hey Big Jim, just 'cause Juniatha's never operated a "J" or a T-1 doesn't mean she's not qualified to comment on 'em. Look, you don't have to get pregnant to qualify as an obstetrician, do you?
And can you believe this thread's gone on to 22 pages? "Shovel in the coal boys, let her roll..."
You don't tug on Superman's cape, and around here, you don't question Juniatha's technical insights.
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
Man! You guys are incorrigable! Left to your own devices you wandered right back into the forrest of dense technical lacunae and automotive lore, no less. Still the discussion of the steam motor was an eye-opener to me and the photos something to conjure with although not particularly "aesthetic". The last three pages of the thread have been all over the ballpark but I will add a few not too technical points. Indeed the PRR did test the N&W J and on the racetrack from Crestline to Chicago via Fort Wayne at that. They agreed the engine did all that was wanted and was fine at 100 mph but they simply could not bring themselves to trust the 70 inch drivers. They had decided they wanted an 80 inch drivered machine since the larger wheel would reduce the rpm count at speed with correspondingly less strain on everything reciprocating and the track. Another little nugget: When C&O gave the Pennsy men the blueprints for the their T-1 they furnished the original drawings and made no mention of many modifications they had made to improve the beast. Pennsy had to go through the teething process all over again before their J-1 was fully up to the mark. Finally I sympathize with the crys of pain and anguish that arose when I ridiculed the Dreyfuss Hudsons but here's the thing. Dreyfuss gives the unmistakeable impression he was trying too hard. The "rocket" look ends up appearing contrived and over the top. Contrast Raymond Lowey's approach to the Pennsy T-1's. It's sleek, powerful, wonderfully appropriate for a fast locomotive and harmonizes with the railroading environment. In a word it's handsome.
Ah, Juniatha, did I catch you out with the reference to the AC-9. Not to worry! Only twelve were ever built and they labored mostly in obscurity on the S.P.'s El Paso-Tumcacari and Modoc Lines. They were "conventional" because they originally burned New Mexico mined coal instead of oil. They were equipped with well proportioned C&O style tenders. Still, they were beauties even though their crews disliked them because the all weather cabs were very hot and stuffy for the mostly desert terrain they operated in.
One final caviat. Just because I say an engine strikes me as ugly doesn't mean I don't like it. All steam is noble! I model the PRR in my basement and one thing that draws me to that prototype is that the "plain to the point of ugly" look is also very purposeful. It bespeaks serious no frills heavy duty down-and-dirty railroading.with a heavy coat of weathering and that's what I try to capture! To see if I've succeeded, go to www.fmrrc.org, click on photo gallery and click on Jim Valle's basement layout. Hope you like it!
Juniatha,If you will go back and read what I wrote you will see that I refered to a limited cut-off. And you should well know what that means. For those who don't, it means that the valve gear was designed to not allow the admission of steam anywhere close to 100% full stroke. The J's were designed for a maximum of 82% cut-off. It could use all of that, so, I guess it depends on how one wants to define "Full Gear".
Now as far as your engineering logic based on physical laws are concerned, I have no question about that at all. What I do question is your making a statement without knowing if it is actually true or not. Just a because a design engineer can crunch some numbers on a slide rule doesn't mean that that is the way it is going to work in real life.
Witness the so-called advanced wheel slip systems of today. It is not unusual that one has to ease off the throttle in order to not overpower track conditions. Or in other words Mother nature once again defeats the best laid plans of mice and men.
Given the wrong rail conditions any locomotive (steam or diesel) can have massive problems with adhesion. So too, given the right rail conditions a loco will have absolutely no problem with adhesion. This I have experianced over my entire 39+ years in train & engine service. As one of my engineer mentors would say "I've been there baby, up and down both sides of that street". And that is what qualifies me to disqualify your blanket statement about "no full gear starting for a J". And, ask why an intelligent person such as yourself would postulate on something you haven't experianced?
If you would like to spend the money on a few recordings, I think you will hear that there are at least a couple out there that has a J making a maximum effort start and not slipping a wheel. And yes to be fair, you will also hear one having problems gaining traction.
BTW, I did not "indirectly let on" to have operated both a J and T1. I have never operated a T1 and I don't brag about the time I operated the 611. Although, I will brag that the N&W Class J #611 is an amazing locomotive and I think that will stand for the entire class of 14 locomotives!
What! No comment on the T1 - Submarine comparison?
I can´t cook a decent meal, but I still like to eat one...
Can we come back to the issue of loco aesthetics, please?
Ah yes, the esthetics! Thanks Sir Madoq for posting the pictures of the 19.10 locomotive. When I saw the discussion starting of a Reichsbahn locomotive with V-2 motors on the side the first thing I thought of was "Was this a collaboration between the Reichsbahn and Werner von Braun and the Peenemunde boys?" Wouldn't THAT have been an interesting esthetic combo? A locomotive with two rockets on either side. However, the reality is just as fascinating. What a pity the thing was scrapped here in the US, what could they have learned from it?
And per DaveK's comment on the "Daylight", well I think the colors look just fine. The silver smokebox is a bit discordant, but still the whole concept works. Ever see pictures of one of those GS engines in the late steam era, all done over in basic black? Bleeeech! Ruins the look totally!
I find a lot to agree with. Again, I like the Daylights. Just like the N&W J and New Haven I-5 a bit better. If course I prefer to see the the SP's 4-8-4's as designed and streamlined. I liek the previous comparison of Pennsy steam streamlining with the Dryfuss J's. I am sorry no T-1 was saved. One should have been. Again, to me it is esthetically a steam locomotive GG-1. And its relationship to the N&W J, New Haven I-5, Daylights, and Royal Hudsons, to me is much liek the relationship esthetically of the GG-1 to the (to me) very beautiful New Haven EP-4 and EF-3 in their original green and gold as delivered.
I only rode once behind a J, and that was from Petersberg to Norfolk at night. I rdoe behind T-1;s on about four occasions, and behind K-4'a on too numerouis occasions to count.
Lets not call Pennsy Power (or Burlington, similar in oddity in general) ugly. Homey or odd, but still very, very lovable. One cananot call the "flying pumps" Pacifics of the C&O beautiful, but they are not ugly. And camelbacks.
And it is paint that makes a Southern PS-4 beautiful. Otherwise it would just be an average Pacific, no better or worse than a typical USRA Pacific.
A person's interests and tastes are mutable. I entered the rail model hobby about seven years ago and quickly decided which railroads appealed to me and which did not. Narrow gauge with their culture and looks...not for me (not yet, I should say). When I first encountered the N&W's J in photographs, I thought to myself, "Yikes! What were they thinking?" Then I saw that Rocket Man style NYC Pacific or Hudson, not sure which, with the great woodman's axe-head runing vertically through the bulbous smokebox. To meself, "Holy crap...what were they thinking?!" Suddenly the J looked much more demure and reserved...even classy. A thing can be tarted up too much...if you know what I mean. And, just as suddenly, my mission for an entire month was to find an HO J to add to my roster...I liked that gal that much. Odd, eh?
I hope you'll agree that, in this photo at least, it looks sleek and fast.
As for the T1, it is one of my favourites, and I will agree with its comparison with a chisel. I have also seen it look a bit like a U-boat, sure, but the nose is what appeals to me. The bulbous intercooler fairing, assuming it hides a couple of pumps and an intercooler , is almost unfortunate, but not fully...it adds to the quirkiness of the entire design. Similarly, the short and sculpted siderods, and the weird valve actuators, also add to the mystique...particularly the left side rear actuator linkage....you have to admit it is a bit odd.
I also find appealing the bevelled side-casing along the 'shoulder' of the boiler. The nose and that casing make the engine look like it was meant to punch through the atmosphere with brute force behind it.
Crandell
....Oh so nice....both of 'em. Would be pleased to have either or both as a model on display in my home office here....Very nice units.
Big Jim: No reason not to brag about having run "The Mighty 611". As the saying goes "It ain't bragging if you can do it!" However, you MIGHT have saved everyone some trouble if you'd said at the outset (if you haven't done so in the past) that you've GOT hands-on experience with the old queen. Establishes your credentials right at the outset, know what I mean? Could save other folks some embarassment too.
It's the reason also that when I make a statement about something I usually mention it's the books that form my opinion, so that folks don't get hot and bothered when they disagree.
I am going to offer up this information and that will be end from me on this off-subject part of this thread.
Pick up the DVD "Hooters on Blue Ridge". At about the six minute mark, you will see engine 605 start a heavy train on the 1.6% grade at Ada, W.Va. on Oct. 10, 1957. As the engine passes you will see valve gear in full forward and no slipping.
This is an excellent DVD in all color & sound. It is one of the best you will find. You won't regret getting this one.
BigJim To quote your latest text : >> If you will go back and read what I wrote you will see that I referred to a limited cut-off.<< I herewith repeat my quoting of your text in your previous comment , the one I was quoting in my previous comment , word for word as follows : >> But then it didn't have full gear capability. Many modern steam locos were designed with limited cut-off. To note : referring to the topical N&W J class you wrote >> But then it didn't have full gear capability. << full stop . The following sentence you explicitly addressed to an unnamed >> many modern steam locos << not the J class nor any other class since you wrote >> many .. locomotiv4es << and as we all know a locomotive is not identical with a class , but a member of a class and that again not necessarily . To be sure : I knew what you wanted to say - only you didn't do it ! Since however in that particular post you let on you know so much better , I didn't want to try and correct you - I left that to yourself and you have done it well . For definition of terms as I understand and use them - open to correction : (a) cut-off : point of mechanical closing of intake given as percentage of total piston travel (b) short cut-off : valve gear closing intake at an early point of piston travel , most generally below some 40 % ( of piston travel ) (c) long cut-off : valve gear closing intake at a late point of piston travel , most generally above some 50 % ( of piston travel ) (d) full cut-off : the longest cut-off in the sense of (c) a given valve gear on a given type of locomotive will provide when reverser is put down ‘to the corner’ ; this by itself does not describe any definite cut-off in percentage of piston travel but just is the longest possible in an existing engine as set up (e) limited cut-off : valve gear by intention set up to provide significantly shorter than usual maximum cut-off in full gear position of reverser , such as 70 .. 65 .. 60 or lower maximum mechanical cut-off as in contrast to regular 75 .. 80 .. 84 , the latter presenting about a practical maximum of what can be designed with Walschaerts valve gear without special adaptations to low speed working or using starter or auxiliary grooves or other devices to lengthen effective cylinder filling over actual cut-off as given by main valve In this context , I read with surprise your note , to quote >> .. you will see that I refered to a limited cut-off. .. The J's were designed for a maximum of 82% cut-off. << Again , your second sentence would compromise your previous sentence since if full cut-off position in the N&W J class specifically provided 82 % then quite clearly this type of locomotive was not built with a limited cut-off feature ! Now , since you wrote you have actually driven # 611 – in second lease of life preserved running , as I presume – why don’t you just state definitely how long a max cut-off did you set it to ? By the way , to quote again from your latest comment : >> And you should well know what that means. For those who don't, it means that the valve gear was designed to not allow the admission of steam anywhere close to 100% full stroke. << Wherein >> it << refers to your previous sentence ending with >> limited cut-off.<< The Walschaerts valve gear by default did not allow admission or intake to attain that high a percentage of piston travel nor would it have been edifying to try and tailor it to do so by using rather odd proportions . Consequentially , not anything below near >> 100 % << was regarded as or defined as limited cut-off . So much for that . Second To quote >> Now as far as your engineering logic based on physical laws are concerned, .. << Thanks , but there are no such “my engineering logic” . Technology makes no distinction as to sex , the same old physical laws apply to anyone , everywhere and in all they do . Quote >> What I do question is your making a statement without knowing if it is actually true or not. << Sad enough if that is your assumption – need I point out it is of course not true . I made my point on a well known grounds of physics and therefore I know that it’s true , anything else would have to be regarded as a miracle and should get attention as to it’s circumstances or rather a check to see where the flaws are in human reception as compared to what really happened ( this applies more often than witnesses would like to admit especially with people maintaining a somewhat skeptical relation to engineering and physical laws ) Quote >> Just a because a design engineer can crunch some numbers on a slide rule doesn't mean that that is the way it is going to work in real life. << If that’s your idea of mechanical engineering , it’s less than appalling – it’s deplorable . We don’t >> crunch some numbers << and by the way >> slide rule << oh , yeah , I inherited one from my late father , however for work we use CAD . Engineering and calculations applied are ever so slightly different from the numbers drawn in a lottery . Third Quote >> Witness the so-called advanced wheel slip systems of today. It is not unusual that one has to ease off the throttle in order to not overpower track conditions. Or in other words Mother nature once again defeats the best laid plans of mice and men.<< There is a saying : you can’t design fool-prove against everything or everyone . Or in reverse : No engine can be designed in a way it can’t be destroyed if an operator so chooses – it’s all result of human brain and effort – of limited knowledge , limited resources , limited construction . If you take a negative look at what >> advanced wheel slip systems of today << cannot do ( really you mean the opposite, I guess – but that’s a Freud’s misspeller that bespeaks intention : wheel slip !) then you look at it the wrong way . Just because a system cannot deal with any possible situation including the most extreme and unlikely one doesn’t mean it is useless , less does it prove engineering in total is nonsense , useless or doesn’t work . You seem to hate engineers , yet in your work – presumably as a diesel driver – you owe a lot of simplification , help and safe-guarding , not to forget comfort to engineering brains having spotted , investigated , designed , tested and finally overcome existing problems , in fact your entire work situation is a result of engineering progress and driving a locomotive out on the road you fully depend on what engineers have designed as a train traction work tool for you ! If an electronic anti-slip control defies to answer an extreme situation it may also be a result of economics having decided to do without a more sophisticated self-controlling system , by intent deciding to leave a wider scope of control to the human factor to avoid drivers would feel disabled or patronized by engine electronics deciding on its own which orders of a driver to comply to and to which extent . So don’t complain if there are situations where you have to use your wits to keep your tonnage rolling . Forth Quote >> Given the wrong rail conditions any locomotive (steam or diesel) can have massive problems with adhesion. So too, given the right rail conditions a loco will have absolutely no problem with adhesion.<< First sentence is trivial . Second is wrong . There is a definite limit of adhesion ( to use the colloquial term – really it’s not adhesion but friction ) that steel wheels can find on steel rails . If tractive effort demand is above that , there is trouble : the locomotive cannot keep up with demand . That can happen any time there is a misjudgment in actual traffic of load / speed / rising grade and engine performance limit . >> This I have experianced over my entire 39+ years in train & engine service. << You mean in 39 years you have never experienced a stall or overload ? >> And that is what qualifies me to disqualify your blanket statement about "no full gear starting for a J".<< Nope , Sir ! (a) you are again misquoting me ! I never wrote you couldn’t drop down to full gear starting a J , in fact that’s what you wrote by yourself , remember your previous comment , to quote : >> But then it didn't have full gear capability.<< So , fair play : don’t shove your miscomposed sentences over to my side ! Why should it not have been possible to use full gear in a N&W J class ? However , what I wrote was : provided there was full boiler pressure available at that moment it would be unwise to use full throttle i e apply all boiler pressure minus small enough throttling pressure drop to steam chest . Based on specific dimensions of this class of locomotive I can clearly state it was more prone to slip under this sort of handling than was a Niagara for instance simply because at that extreme setting of controls a N&W J would exert a much higher specific tractive effort per unit of adhesion mass than the latter and based on average dry rail conditions this extra amount of specific torque at wheel rim would provoke at least a borderline case if not more likely it would be above adhesion limit . My statement is not >> blanket << but based on facts , therefore I keep that up , full stop . (b) As you choose to use misquotations you disqualify yourself for offering a better view on the matter at hand . Side remark : You seem to retain a notion it were telling of a specific quality in the design of a steam locomotive if the engine would allow for this rude sort of handling . It does not . If an engine does not slip on dry rails using full gear ( provided for now this was 75 % or over ) and full throttle at the same time when starting , there is but one thing it tells an engineer and that is : cylinder volume is inadequate for getting best low to medium speed performance from a given boiler output . If you want to look at it this way , that condition was present in the production series Niagaras . Yet , it was allowed for since main interest was in continued daily high speed running and to optimize performance in the upper speed range a degree of loss in low speed hard pulling output was allowed for . Mind that any reduction in full pressure piston load allows for accordingly reduced reciprocating masses and that directly leads to reduction of mass inertia forces in running gear , axles and chassis – a big advantage to maintenance , lower wear and improved longevity of an engine ( if in the end it became meaningless because of premature scrapping this was not for technical reasons but in consequence of commercial decisions to abandon steam ) Add,: Quote >> If you would like to spend the money on a few recordings, I think you will hear that there are at least a couple out there that has a J making a maximum effort start and not slipping a wheel.<< I have a few recordings – although I missed out one LP I saw in an antiques shop in Goodge Street in London when I strolled around fashion and vinyls shopping . As far as I remember it was titled “Steam and thunder” and featured a night picture of a N&W A or Y , the flip-side read it contained recordings of N&W freight on grades in the Alleghennies in a thunderstorm . Sounded promising , yet I found my money was all spent with that last pair of jeans and fancy pullover , I asked the guy to put it aside , intending to return the other day – but that was when we had to leave . Still I can imagine the sound of a J class pulling at all out effort - yet that doesn’t prove anything about using full throttle and full gear at the same time when it would appear more sensible to use something around ¾ of b p while at full cut-off . Side remark : If you would have tried the like on any . but any ! , European Pacific you’d have got a vicious wheel spin and gained nothing but trouble . As by what I have learned from knowledgeable engineers and loco crews in France , Germany and Poland and by some – admittedly quite limited first hand experience by my own ( I have come late but not too late ) I may summon : Typically , an SNCF four cylinder compound Pacific was started on no more than half throttle ( meaning half of b p ) until receiver filler valve was closed and the engine worked in compound mode – then on dry rails something like ¾ throttle was applied until cut-off was brought in and throttle fully opened . On a German 01 class Pacific , usual starting procedure was to drop down to some 60 % or over according to train length ( of a maximum of 81 % ) and throttle would be cracked open to admit some 50 – 60 % of b p to steam chest ( on wet rails ; no more than 2/3 of b p on dry rails ) – very much likewise on 52 class light Decapods . This does not indicate these engines were lacking power in relation to engine service mass – on the contrary : they exerted full tractive effort at these throttle settings already . Now , when notching up , it was possible to compensate by opening throttle further and that allowed to much keep up tractive effort than if there was no reserve as with full throttle / full gear starting . Also , it allowed for running a 44 class three cylinder heavy Decapod up a ramp at some 25 mph on full throttle and no more than 40 % cut-off since that already gave all the tractive effort that was safe to apply in view of adhesion limit – thus using steam more economical than in an engine that would do the same only on much longer or full cut-off and full throttle and since in reciprocal saving steam increased power output per mass unit of steam per hour it provided for a very high percentage of maximum output present in high effort / low speed ramp performance . No insult intended , by all means I’m prepared to discuss steam loco specs and design – only : it should be down to facts , the real McCoy , no vague reproaches or affronts please . Regards
BigJim
To quote your latest text :
>> If you will go back and read what I wrote you will see that I referred to a limited cut-off.<<
I herewith repeat my quoting of your text in your previous comment , the one I was quoting in my previous comment , word for word as follows :
>> But then it didn't have full gear capability. Many modern steam locos were designed with limited cut-off.
To note : referring to the topical N&W J class you wrote >> But then it didn't have full gear capability. << full stop . The following sentence you explicitly addressed to an unnamed >> many modern steam locos << not the J class nor any other class since you wrote >> many .. locomotiv4es << and as we all know a locomotive is not identical with a class , but a member of a class and that again not necessarily .
To be sure : I knew what you wanted to say - only you didn't do it ! Since however in that particular post you let on you know so much better , I didn't want to try and correct you - I left that to yourself and you have done it well .
For definition of terms as I understand and use them - open to correction :
(a) cut-off : point of mechanical closing of intake given as percentage of total piston travel
(b) short cut-off : valve gear closing intake at an early point of piston travel , most generally below some 40 % ( of piston travel )
(c) long cut-off : valve gear closing intake at a late point of piston travel , most generally above some 50 % ( of piston travel )
(d) full cut-off : the longest cut-off in the sense of (c) a given valve gear on a given type of locomotive will provide when reverser is put down ‘to the corner’ ; this by itself does not describe any definite cut-off in percentage of piston travel but just is the longest possible in an existing engine as set up
(e) limited cut-off : valve gear by intention set up to provide significantly shorter than usual maximum cut-off in full gear position of reverser , such as 70 .. 65 .. 60 or lower maximum mechanical cut-off as in contrast to regular 75 .. 80 .. 84 , the latter presenting about a practical maximum of what can be designed with Walschaerts valve gear without special adaptations to low speed working or using starter or auxiliary grooves or other devices to lengthen effective cylinder filling over actual cut-off as given by main valve
In this context , I read with surprise your note , to quote >> .. you will see that I refered to a limited cut-off. .. The J's were designed for a maximum of 82% cut-off. <<
Again , your second sentence would compromise your previous sentence since if full cut-off position in the N&W J class specifically provided 82 % then quite clearly this type of locomotive was not built with a limited cut-off feature !
Now , since you wrote you have actually driven # 611 – in second lease of life preserved running , as I presume – why don’t you just state definitely how long a max cut-off did you set it to ?
By the way , to quote again from your latest comment : >> And you should well know what that means. For those who don't, it means that the valve gear was designed to not allow the admission of steam anywhere close to 100% full stroke. <<
Wherein >> it << refers to your previous sentence ending with >> limited cut-off.<<
The Walschaerts valve gear by default did not allow admission or intake to attain that high a percentage of piston travel nor would it have been edifying to try and tailor it to do so by using rather odd proportions . Consequentially , not anything below near >> 100 % << was regarded as or defined as limited cut-off .
So much for that .
Second
To quote >> Now as far as your engineering logic based on physical laws are concerned, .. <<
Thanks , but there are no such “my engineering logic” . Technology makes no distinction as to sex , the same old physical laws apply to anyone , everywhere and in all they do .
Quote >> What I do question is your making a statement without knowing if it is actually true or not. <<
Sad enough if that is your assumption – need I point out it is of course not true . I made my point on a well known grounds of physics and therefore I know that it’s true , anything else would have to be regarded as a miracle and should get attention as to it’s circumstances or rather a check to see where the flaws are in human reception as compared to what really happened ( this applies more often than witnesses would like to admit especially with people maintaining a somewhat skeptical relation to engineering and physical laws )
Quote >> Just a because a design engineer can crunch some numbers on a slide rule doesn't mean that that is the way it is going to work in real life. <<
If that’s your idea of mechanical engineering , it’s less than appalling – it’s deplorable . We don’t >> crunch some numbers << and by the way >> slide rule << oh , yeah , I inherited one from my late father , however for work we use CAD . Engineering and calculations applied are ever so slightly different from the numbers drawn in a lottery .
Third
Quote >> Witness the so-called advanced wheel slip systems of today. It is not unusual that one has to ease off the throttle in order to not overpower track conditions. Or in other words Mother nature once again defeats the best laid plans of mice and men.<<
There is a saying : you can’t design fool-prove against everything or everyone . Or in reverse : No engine can be designed in a way it can’t be destroyed if an operator so chooses – it’s all result of human brain and effort – of limited knowledge , limited resources , limited construction .
If you take a negative look at what >> advanced wheel slip systems of today << cannot do ( really you mean the opposite, I guess – but that’s a Freud’s misspeller that bespeaks intention : wheel slip !) then you look at it the wrong way . Just because a system cannot deal with any possible situation including the most extreme and unlikely one doesn’t mean it is useless , less does it prove engineering in total is nonsense , useless or doesn’t work . You seem to hate engineers , yet in your work – presumably as a diesel driver – you owe a lot of simplification , help and safe-guarding , not to forget comfort to engineering brains having spotted , investigated , designed , tested and finally overcome existing problems , in fact your entire work situation is a result of engineering progress and driving a locomotive out on the road you fully depend on what engineers have designed as a train traction work tool for you ! If an electronic anti-slip control defies to answer an extreme situation it may also be a result of economics having decided to do without a more sophisticated self-controlling system , by intent deciding to leave a wider scope of control to the human factor to avoid drivers would feel disabled or patronized by engine electronics deciding on its own which orders of a driver to comply to and to which extent . So don’t complain if there are situations where you have to use your wits to keep your tonnage rolling .
Forth
Quote >> Given the wrong rail conditions any locomotive (steam or diesel) can have massive problems with adhesion. So too, given the right rail conditions a loco will have absolutely no problem with adhesion.<<
First sentence is trivial . Second is wrong . There is a definite limit of adhesion ( to use the colloquial term – really it’s not adhesion but friction ) that steel wheels can find on steel rails . If tractive effort demand is above that , there is trouble : the locomotive cannot keep up with demand . That can happen any time there is a misjudgment in actual traffic of load / speed / rising grade and engine performance limit .
>> This I have experianced over my entire 39+ years in train & engine service. << You mean in 39 years you have never experienced a stall or overload ?
>> And that is what qualifies me to disqualify your blanket statement about "no full gear starting for a J".<<
Nope , Sir !
(a) you are again misquoting me ! I never wrote you couldn’t drop down to full gear starting a J , in fact that’s what you wrote by yourself , remember your previous comment , to quote : >> But then it didn't have full gear capability.<< So , fair play : don’t shove your miscomposed sentences over to my side !
Why should it not have been possible to use full gear in a N&W J class ? However , what I wrote was : provided there was full boiler pressure available at that moment it would be unwise to use full throttle i e apply all boiler pressure minus small enough throttling pressure drop to steam chest . Based on specific dimensions of this class of locomotive I can clearly state it was more prone to slip under this sort of handling than was a Niagara for instance simply because at that extreme setting of controls a N&W J would exert a much higher specific tractive effort per unit of adhesion mass than the latter and based on average dry rail conditions this extra amount of specific torque at wheel rim would provoke at least a borderline case if not more likely it would be above adhesion limit . My statement is not >> blanket << but based on facts , therefore I keep that up , full stop .
(b) As you choose to use misquotations you disqualify yourself for offering a better view on the matter at hand .
Side remark :
You seem to retain a notion it were telling of a specific quality in the design of a steam locomotive if the engine would allow for this rude sort of handling . It does not . If an engine does not slip on dry rails using full gear ( provided for now this was 75 % or over ) and full throttle at the same time when starting , there is but one thing it tells an engineer and that is : cylinder volume is inadequate for getting best low to medium speed performance from a given boiler output . If you want to look at it this way , that condition was present in the production series Niagaras . Yet , it was allowed for since main interest was in continued daily high speed running and to optimize performance in the upper speed range a degree of loss in low speed hard pulling output was allowed for . Mind that any reduction in full pressure piston load allows for accordingly reduced reciprocating masses and that directly leads to reduction of mass inertia forces in running gear , axles and chassis – a big advantage to maintenance , lower wear and improved longevity of an engine ( if in the end it became meaningless because of premature scrapping this was not for technical reasons but in consequence of commercial decisions to abandon steam )
Add,:
Quote >> If you would like to spend the money on a few recordings, I think you will hear that there are at least a couple out there that has a J making a maximum effort start and not slipping a wheel.<<
I have a few recordings – although I missed out one LP I saw in an antiques shop in Goodge Street in London when I strolled around fashion and vinyls shopping . As far as I remember it was titled “Steam and thunder” and featured a night picture of a N&W A or Y , the flip-side read it contained recordings of N&W freight on grades in the Alleghennies in a thunderstorm . Sounded promising , yet I found my money was all spent with that last pair of jeans and fancy pullover , I asked the guy to put it aside , intending to return the other day – but that was when we had to leave .
Still I can imagine the sound of a J class pulling at all out effort - yet that doesn’t prove anything about using full throttle and full gear at the same time when it would appear more sensible to use something around ¾ of b p while at full cut-off .
If you would have tried the like on any . but any ! , European Pacific you’d have got a vicious wheel spin and gained nothing but trouble . As by what I have learned from knowledgeable engineers and loco crews in France , Germany and Poland and by some – admittedly quite limited first hand experience by my own ( I have come late but not too late ) I may summon : Typically , an SNCF four cylinder compound Pacific was started on no more than half throttle ( meaning half of b p ) until receiver filler valve was closed and the engine worked in compound mode – then on dry rails something like ¾ throttle was applied until cut-off was brought in and throttle fully opened . On a German 01 class Pacific , usual starting procedure was to drop down to some 60 % or over according to train length ( of a maximum of 81 % ) and throttle would be cracked open to admit some 50 – 60 % of b p to steam chest ( on wet rails ; no more than 2/3 of b p on dry rails ) – very much likewise on 52 class light Decapods . This does not indicate these engines were lacking power in relation to engine service mass – on the contrary : they exerted full tractive effort at these throttle settings already . Now , when notching up , it was possible to compensate by opening throttle further and that allowed to much keep up tractive effort than if there was no reserve as with full throttle / full gear starting . Also , it allowed for running a 44 class three cylinder heavy Decapod up a ramp at some 25 mph on full throttle and no more than 40 % cut-off since that already gave all the tractive effort that was safe to apply in view of adhesion limit – thus using steam more economical than in an engine that would do the same only on much longer or full cut-off and full throttle and since in reciprocal saving steam increased power output per mass unit of steam per hour it provided for a very high percentage of maximum output present in high effort / low speed ramp performance .
No insult intended , by all means I’m prepared to discuss steam loco specs and design – only : it should be down to facts , the real McCoy , no vague reproaches or affronts please .
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