railracerUP also went from a lot of 4" flues ( 177) and few 2-1/4"tubes (45) in series 3 and 4 to a lot of tubes (177) and fewer flues( around 60?) in series 5. They also went back to the Type A superheater, so I'm not sure if that was just to accomodate the type A or if more tubes were better at making steam than a lot of flues?
I personally suspect some of the 'adjustment' might have involved excessive superheat, or excessive warpage or 'cutting' of elements, with the engines being run at higher loads and speeds. The effective FGA between a given area of tubes and a "loaded" flue with elements changes with speed, which can result in the development of what Ross Rowland sometimes called 'crazy high' superheat when large locomotives like 614 were worked at high speed and a 'power' level of cutoff for suitable mass flow for a heavy consist. It would make sense to adjust the proportions once to suit any worst-case problems "forensically" observed.
I do not know for sure whether WPA restrictions made 'scarce wartime alloys' hard enough to get that the type E was too expensive or difficult to maintain, in addition to being 'too efficient for its own good' under some conditions. There are certainly people who would know this on RyPN.
Overmod When you're a bit more comfortable with how flame 'works' in these boilers, look at some of the 'patent' circulation arrangements (like Nicholson syphons and American Arch 'security circulators' to see the conjoined advantages and drawbacks of circulating water through the radiant plume. You will not be surprised to see why there can be enhanced sooting when those things are too enthusiastically (or erroneously) provided. (Incidental solution-left-to-the-reader exercise: the original implementations of arch tubes continued straight up to the inner wrapper near the top of the backhead, seemingly a nifty place to absorb a few radiant BTU at fourth-power Stefan-Boltzmann uptake. But many railroads, including ATSF, quietly abandoned that idea. Can you tell why?
When you're a bit more comfortable with how flame 'works' in these boilers, look at some of the 'patent' circulation arrangements (like Nicholson syphons and American Arch 'security circulators' to see the conjoined advantages and drawbacks of circulating water through the radiant plume. You will not be surprised to see why there can be enhanced sooting when those things are too enthusiastically (or erroneously) provided.
(Incidental solution-left-to-the-reader exercise: the original implementations of arch tubes continued straight up to the inner wrapper near the top of the backhead, seemingly a nifty place to absorb a few radiant BTU at fourth-power Stefan-Boltzmann uptake. But many railroads, including ATSF, quietly abandoned that idea. Can you tell why?
I took a look at some of the stats between the different Challenger series and noticed the series 5 Challengers had some differences from the series 3 and 4 Challengers.
One of which was reducing the surface area of the circulators from around 80 sq. ft to about 44 sq. ft. Kratville mentions this as an attempt to improve firing. I guess UP figured out the combustion quenching effect was costing more than the enhanced circualtion was gaining?
UP also went from a lot of 4" flues ( 177) and few 2-1/4"tubes (45) in series 3 and 4 to a lot of tubes (177) and fewer flues( around 60?) in series 5.
They also went back to the Type A superheater, so I'm not sure if that was just to accomodate the type A or if more tubes were better at making steam than a lot of flues?
Thank you Overmod for the recommendation to look for Eugene Huddleston's book. I found a copy on ebay and have been thoughly enjoying it.
railracer I've really been enjoying the machine side of the discussion, but I think you bring up a great point about the human side as well. There are plenty of pictures of "Jabelmann Power" shooting roiling columns of thick smoke skyward, but also many showing a "light" stack. All the machine and fuel shortcomings aside, a good fireman definitely made a big impact. By the 1950's many of the more senior engine crews were transitioning to diesels, which were the more desried jobs. This left the younger, less experienced crews to the Challengers and Big Boys.
I've really been enjoying the machine side of the discussion, but I think you bring up a great point about the human side as well. There are plenty of pictures of "Jabelmann Power" shooting roiling columns of thick smoke skyward, but also many showing a "light" stack.
All the machine and fuel shortcomings aside, a good fireman definitely made a big impact. By the 1950's many of the more senior engine crews were transitioning to diesels, which were the more desried jobs. This left the younger, less experienced crews to the Challengers and Big Boys.
Wasn't there something in one of the Steam Glory series or some other place where the Union Pacific had to substitute steam for first-gen diesels when they would have breakdowns? And the crews had to back-transition to steam -- like riding a bicycle, you never forget, but do you get rusty without current experience?
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
Overmod I stopped flying sailplanes when I realized, to my horror, that I could no longer recognize the changing terrain without frequent orientation using a map. Sailplanes require fairly frequent turns where you have to be sensitive to ridge and thermal lift and not concentrating on 'where you are going' -- and you might be pointing 'anywhere' once you have come to altitude. On the other hand when you commit to land there is usually no such thing as a go-round, and it becomes much more tedious to recover the aircraft the further away from the staging point you come to rest -- further both horizontally and vertically. Helicopters require more multiple control haptics than sailplanes...
I stopped flying sailplanes when I realized, to my horror, that I could no longer recognize the changing terrain without frequent orientation using a map.
Sailplanes require fairly frequent turns where you have to be sensitive to ridge and thermal lift and not concentrating on 'where you are going' -- and you might be pointing 'anywhere' once you have come to altitude. On the other hand when you commit to land there is usually no such thing as a go-round, and it becomes much more tedious to recover the aircraft the further away from the staging point you come to rest -- further both horizontally and vertically.
Helicopters require more multiple control haptics than sailplanes...
I did some sailplane flying out of Sugarbush, VT back in the mid 70s when I was 14-15 years old. I used the "iron compass" to navigate as the surrounding mountains and towns all seemed to blend together as one at about 2500 ft. With so many rail abandonments over the intervening decades I wonder if the old "iron compass" is even an option these days.. probably not..
$150 plus $3.99 shipping does not strike me as excessively pricy. I stumbled across a source selling brand new ones in shrink wrap for $99 about a decade ago, and all the 'serious correspondents' on the old steam_tech Yahoo group were overjoyed to get one at that price.
It's the 1938 French original that commands the astronomical price.
La Locomotive a Vapeur: English Edition: Chapelon, Andre, Carpenter, George: 9780953652303: Amazon.com: Books
that are still pricey, I cannot tell if this is in the original French or is an English-language translation.
These would be the translation since George Carpenter was the translator.
His name would not appear on the listing of an original version.
Peter
Paul MilenkovicCinder cutting? Poor access to water side for descaling? Burn-through of the tubes?
There should be little cinder cutting as this is just about the hottest net part of the fire, where the plume coming up under the arch reverses direction to go forward under the crown. If anything you'd get glassing there if the ash is fusible.
The designs I've seen all have very careful provision of washout plugs on the backhead that line up with the tubes. That might actually have exacerbated the problem... but it made scaling an easy thing to rectify.
One of the most evil things in a staybolted firebox is the development of DNB, departure from nucleate boiling. Steam is a relatively good insulator, as anyone evennpassingly familiar with the Eisenhoffer/Leidenfrost effect knows. In DNB a larger and larger area flashes to steam, while the plate behind that area begins to overheat -- possibly very severely very fast.
The bright principle behind the arch tubes were to use them as longitudinal bars to hold the arch up and get a little extra free vertical circulation. But look at the situation a moment:
Water flow IN comes from a restricted volume at the throat;
The section of pipe above the arch is in a relatively high radiant heat flux, very subject to induced DNB;
The exit of the pipe butt-ends into the backhead space, virtually a flow stall for natural circulation in a pipe.
Note what happens when a relatively large mass of steam forms as a 'plug' in the hot upper bore -- it is above saturation pressure pretty quickly and this presses down against the natural-circulation rise of heated water as well as up toward the backhead. Expect to see thermal cycling -- lots and lots of thermal cycling!
A similar mechanism was in my opinion a likely cause of or contributor to the explosion of Allegheny 1642. One touted 'advantage' of Nicholsons was that in conditions of very low water their 'pumping action' would cause a welling-up that would tend to keep the crown covered... in fact, to amplify the tendency for the boiler to work more effectively than it already does with shallow water over the crown.
What actually happens is that the welling doesn't fully cover the crown; it spills this way and that, tending more and more to avoid overheated sections but quenching them fairly effectively when in contact. Steel generally doesn't like repeated overheating and quenching when under monotone load... it deforms and cracks and deforms...
Overmod (Incidental solution-left-to-the-reader exercise: the original implementations of arch tubes continued straight up to the inner wrapper near the top of the backhead, seemingly a nifty place to absorb a few radiant BTU at fourth-power Stefan-Boltzmann uptake. But many railroads, including ATSF, quietly abandoned that idea. Can you tell why?
Cinder cutting? Poor access to water side for descaling? Burn-through of the tubes?
Thanks for the references.
Looks like I have some "homework" to do!
Beware of studying resources for firing pulverized coal in a Benson boiler. The load characteristics, turndown, heat balance and Rankine-cycle implementation are very different from most locomotive practice.
Start by reading this carefully, including memorization of as many of the backhead controls as you can:
https://www.railarchive.net/firing/
Then peruse this for the non-US-American view (I miss Claude Bersano so badly!)
http://users.fini.net/~bersano/english-anglais/HandbookForRailwaySteamLocomotiveEnginemen-BTC-1957-pg196.pdf
You might look into the reprinted 1947 Reading Railroad 'Firing the Steam Locomotive' (about $10 from Amazon but you may find a used copy from time to time from a place like Thriftbooks for less) which has some detail differences.
The overfire jets were never intended for thermodynamic performance: they are purely to avoid fines for visible smoke from the (many!) places that started imposing them. Note that there are two kinds of those guns/jets: those that use boiler steam to entrain atmosphere (doing some secondary-air preheat, but adding water to the flame and taking it away from the boiler, neither of which are good) vs. those that use main-reservoir brake air (terrible shrieking and the usual substantial chill as 140psi air exhausts to a partial vacuum, but a higher mass flow of burnable oxygen). I have always been a bit amused with the idea that the jets penetrate to the center of the gas plume, and that they don't disturb the gasdynamics of induced draft... neither of which really happen.
On the other hand, heating the primary air can be useful, just as it is for PC firing in high-pressure utility boilers (where there is room and power to arrange adequate 650F or better primary air without difficulties). An interesting device for Super-Power engines is the Snyder preheater, from the early Thirties but not gaining real traction til the late Forties, which is basically 3 staggered passes of 2" pipe with exhaust steam saturated at typical exhaust backpressure run through them arranged in the gap between mud ring and ashpan. Apparently C&O observed better than 10% saving (admittedly this is only about 0.7% overall gain based on the stoic heat content of the fuel, but it's a great dollar saving for what is basically a few tens of feet of pipe).
Happy Fathers Day to all!
Just to help my own learning on the subject. I found an online articel that describes firing practices for different types of coal.
This is for stationary plants, far different than locomotives, but i'm guessing the general concepts pertain, but with even more complexity!
It seems the more volatile matter, the more air and volume is needed for efficient combustion. The more organic matter the thinner the fire needed. The article mentions Rock Springs coal specifically and states that 6-8" is ideal.
To Overmods point, with the throttle wide open and at high cutoff, I could see where it would be easy to tear holes in the fire. The articel also mentions the air needs to be very hot, ambient air will stop the combustion process. So holes in the fire would be very bad indeed.
That also I think answers a question I had about why the overfire air holes were eliminated started around 1948. Gordon McCulloh mentions it in his book A History of Union Pacific Steam but didn't mention why. All that cold air coming in the sides of the firebox was probably hurting combustion rather than helping. Sounds like focusing on good, hot primary are was more beneficial.
Again, many you you probably already understand these things, but the article was helpful for a novice like me.
The article link is here
https://www.gutenberg.org/files/22657/22657-h/chapters/coal.html
Thanks Overmod
Paul,
Thank you for the references!
selector Guess...no really...guess why he failed out at CFOCS.
OK, map reading and land navigation?
When I was at The Basic School (For Marine Officers) the word was land navigation and map reading was the ONLY thing you had to pass to get out of there!
SD70Dude ... They learned on the fly, some 'got it' and some didn't. The same is true for Engineers, some guys never learned how to run a locomotive efficiently, and others delighted in making the Fireman's life far more difficult than necessary.
...
They learned on the fly, some 'got it' and some didn't. The same is true for Engineers, some guys never learned how to run a locomotive efficiently, and others delighted in making the Fireman's life far more difficult than necessary.
During my Basic Officer Training when Canadian Forces Officer Candidate School (CFOCS) was in Chilliwack, we were four to a room in barracks. One of my roommates was hoping to be a helicopter pilot. He was an engineer, but in cartography. Guess...no really...guess why he failed out at CFOCS.
Paul Milenkovic, everything is better with cheddar! Have a great Father's Day behind The Cheddar Curtain!
Paul Milenkovic...instead of "Late" meaning the second major batch of locomotive production, it could possibly mean that the train is late, that is, behind schedule.
Happy Dad's Day!
Paul Milenkovic I finally figured it out about why the late Challengers smoke so much and go through large amounts of fuel in relation to the early Challengers. A crew on a late Challenger is under pressure to make up time, so the fireman may stoke too much coal on the fire?
I finally figured it out about why the late Challengers smoke so much and go through large amounts of fuel in relation to the early Challengers.
A crew on a late Challenger is under pressure to make up time, so the fireman may stoke too much coal on the fire?
"Early" and "Late" could have a double meaning, where instead of "Late" meaning the second major batch of locomotive production, it could possibly mean that the train is late, that is, behind schedule.
In honor of all of the dads out there on Fathers' Day, I offer this as a "dad joke", meaning a G-rated joke you can tell your young children but one that is otherwise not terribly funny.
A "dad joke" told by an airline pilot following a similar bit of comedic reasoning was just told on Rand Simberg's Transterrestrial Musings. A Southwest Airlines pilot pointed out the Arizona Meteor crater to the passengers on one side of the airplane who could see it, reminding that that a meteor excavated that gigantic crater some 50,000 years ago, but what is even more amazing, it just missed that little house.
I hope you enjoy your stay, and I will be here all week.
I'm really enjoying this discussion on how thermodynamics applies to steam locomotives.
It stands in stark contrast to the 'training' programs of many railroads during the steam era, where a new Fireman would write a basic rules and theory exam, make as few as three student trips, and then start working regularly.
Greetings from Alberta
-an Articulate Malcontent
Paul MilenkovicA crew on a late Challenger is under pressure to make up time, so the fireman may stoke too much coal on the fire?
Remember that the fire in a locomotive is not at all what you think of. It is not flames dancing on a hearth, or burner fire as in an incinerator. It is a white sheet of vaporized lambent carbon, glowing as a blackbody, suspended by a combination of physics ideally just out of contact with relatively cold boiler and chamber inner sheet surfaces, and ideally 'going out' by finishing combustion to full CO2 (which, remember, is transparent for EM of many wavelengths) just as it gets to the rear tubesheet.
Now, we watch our hypothetical firing practice start falling behind, and note that the steam pressure is starting to fall, so we stoke 'more and more' until the bed is heavy. This decreases primary air and chills the top of the firebed; the combination reducing the gas flow through the hot carbon. Draft is likely increased as a consequence of what made the steam pressure start to fall -- WOT with the reverse inching toward the corner to keep speed -- but the relaxation now has an increased component of 'various' secondary-air sources, some of which will be increasing the 'gas flow' across the distributing table of the stoker... where the elevator worm is completing the crunching-up of the subbituminous and likely discharging it with a relatively high component of fines.
(I pause briefly to remind everyone that the firebox volume is purposely run as a reducing atmosphere below atmospheric pressure)
Now what you'll see in this situation is increased fines lifting, trying to light off in the gas flow, but largely not succeeding in scrubbing gas to get adequate carburetor in the reducing atmosphere before their TOF brings them to the tubes where luminous combustion is quickly quenched (all reference I've seen say within 6"; some competent engineers including Matt Austin say 'virtually immediately' as far as heat transfer in the tubes is concerned). That does not mean the particles are extinguished; only that they're not glowing -- in fact, when ejected from the front end they may happily reignite spontaneously, which is what Goss referred to as 'sparks' and what produces the lovely effects of the Chinese engines.
Of course the tonnage of fuel that we see reigniting in the air contributes nothing to the locomotive's thermodynamics, but adds to the fuel bill just as if it did.
Flintlock76 A person will believe everything they read in a newspaper until they read an article about a subject near and dear to that persons heart where the writer gets it all wrong. Then the trust is damaged or gone forever, never to return. "If they got the subject I know about all wrong, what else are they getting wrong?"
A person will believe everything they read in a newspaper until they read an article about a subject near and dear to that persons heart where the writer gets it all wrong. Then the trust is damaged or gone forever, never to return.
"If they got the subject I know about all wrong, what else are they getting wrong?"
Which reminds me of my Palomar Mountain vs Mt Palomar rule for publications. The publications that use the former are making an effort to get the details right, where with publications that use the latter makes me wonder of what other details are wrong.
In th railfan world, the comparison might be Grand Central Terminl vs Grand Central Station.
Paul MilenkovicThe distillation of the Gell-Mann effect is that if you have expert knowledge of a field, you will find that journalists have a third-grade level of misunderstanding of it, which should lead you to believe that the preponderance of what is in the newspaper is only loosely connected to what an expert would know to be true on any subject reported upon.
Reminds me of a comment I read years ago, by I don't remember who:
Part of the 'key' is that engineering and historiography are very different disciplines and should be conflated with great care and circumspection. This works, as with Feynman and Gell-Mann, both ways.
When we question a high-speed claim with steam, we can look to physics and thermodynamics to assess if a particular 'historical' claim is valid... but we have to be careful about what assumptions we use in modeling or experimentation. We can likewise correct for historical mistakes or design compromises, as was done in the early months of the T1Trust effort to be sure a 'practical' duplex could be engineered and built if it turned out (as it has not, so far) that the T1 as designed and improved by PRR had critical flaws impossible to cure.
One of the 'historical' smoking guns with the T1 is almost certainly the departure of Deasy and, in consequence a few months later, Duer. From that point forward we can date the abandonment of much of the steam research and practical betterment efforts, including the suite of detail-design improvements set to fix the major operational issues in first-line service in 1948... the engines would not see first-line service 'ever any more' under Symes, and I suspect some of the seeds of the too-convenient-failure explanation to get out of the equipment-trust obligation were being sown even then...
I have to work, but I'll get back to this interesting set of your observations later.
Overmod When I say 'echoing Bruce' I don't mean just citing the reference from American Locomotives. Bruce, God bless him, had a tendency to claim things for Alco done 'on his watch' that might be... shall we say a tad self-serving. Does Withuhn repeat his claim that he observed the Milwaukee A run at better than 128mph... more than once? Mr. Withuhn, as I recall, early in his career stated unconditionally that T1s ran 125mph, and I believe he unquestioningly accepted Baldwin's assertion that the ATSF 3460 class were '120mph' locomotives, both of which caused me considerable grief in my youth until I determined for myself that their basis (like Crosby's story about a 120mph speedometer) was not entirely objectively demonstrable, at least not with any scholarly proof, citation or otherwise.
When I say 'echoing Bruce' I don't mean just citing the reference from American Locomotives. Bruce, God bless him, had a tendency to claim things for Alco done 'on his watch' that might be... shall we say a tad self-serving. Does Withuhn repeat his claim that he observed the Milwaukee A run at better than 128mph... more than once?
Mr. Withuhn, as I recall, early in his career stated unconditionally that T1s ran 125mph, and I believe he unquestioningly accepted Baldwin's assertion that the ATSF 3460 class were '120mph' locomotives, both of which caused me considerable grief in my youth until I determined for myself that their basis (like Crosby's story about a 120mph speedometer) was not entirely objectively demonstrable, at least not with any scholarly proof, citation or otherwise.
Are you saying I am succumbing to the Gell-Mann effect?
Richard Feynman, who was a Nobel Laureate Caltech physicist, recruited Murray Gell-Mann to join him on the faculty of Caltech, hence becoming another Nobel Laureate Caltech physicist. Hard to say if they were good friends who were just kidding around or if they began to regard each other as rivals in scientific glory, but a Gell-Mann interview had him criticizing Feynman, who had preceded him in passing on, for a number of personal and social foibles, including Feynman's theories about dental hygiene.
Feynman didn't just "take it", he apparently made public how Gell-Mann was naive and eccentric, although the story was passed along by the late Harvard Medical School graduate and best selling author of sci-fi thrillers Michael Crichton.
The account is that Gell-Mann would accept at face value what he read about the Middle East whereas when he saw an article about physics research in the New York Times, he pounded his fist on the table saying, "Richard, every last thing in that article is just plain wrong! Why didn't they ask me for clarification of those points before going with it!"
Feynman thought his colleague Gell-Mann to be hopelessly naive to think that the article on the Middle East could be accepted at face value and wasn't equally a distortion owing to reporters at the New York Times knowing as little about the Middle East as they did about Physics breakthroughs.
Feynman was also invoking a principle well known in physics, that if a physical law, such as gravity, applied on Earth, the same law of gravity should apply to the swarm of stars circling a remote galaxy, that is, unless there is a reason to believe that "physics" worked differently at this remote location. Actually, the whole thing about Dark Matter is that it appears that gravity does works differently, and the physicists who crack that puzzle will be nominated for the Nobel Prize.
The distillation of the Gell-Mann effect is that if you have expert knowledge of a field, you will find that journalists have a third-grade level of misunderstanding of it, which should lead you to believe that the preponderance of what is in the newspaper is only loosely connected to what an expert would know to be true on any subject reported upon.
So am I naive that I accept Bruce's claims about the exploits of ALCo steam at face value, or that I am trusting of Withuhn's tall tales of the T1? Besides my research-engineering comic-book superhero Spidey sense, I think I have read enough skepticism to say, no, maybe the 999 didn't crack the 100 MPH or if it did, it didn't go 112 MPH, and Withuhn explains the mechanics of timing along with confirmation bias of persons observing mile markers and not even using proper stop watches used in racing or sporting events.
My Robin-sidekick-to-Batman remark about citations is that Withuhn has such dense citations to Bruce, Withuhn isn't just echoing Bruce, large sections of Withuhn are cribbed from Bruce, which I guess is OK for a history scholar if you include all the cites, but maybe a person should just read Bruce?
Overmod Incidentally, Withuhn appears to be echoing Mr. Bruce in saying Alco 'invented' the idea of removing vertical hinging on the forward engine and accommodating vertical curvature entirely in the equalization. The A was designed for high speed, and uses this feature implicitly to achieve running stability.
Incidentally, Withuhn appears to be echoing Mr. Bruce in saying Alco 'invented' the idea of removing vertical hinging on the forward engine and accommodating vertical curvature entirely in the equalization. The A was designed for high speed, and uses this feature implicitly to achieve running stability.
Holy scholarly citation, Batman! The Withuhn book is one citation after another of the Alfred Bruce book.
Our community is FREE to join. To participate you must either login or register for an account.