ACYThey seemed to think "Coal is coal". My dad would say "bad coal is dirt; good coal is fuel".
Our fathers should have met or maybe they did in a better place. Mine spent 35 years as an engineer on steam and later, of course, Diesel tow boats pushing coal from WV mines to Pittsburgh steel mills. His opinion of coal was about like your dad's. By the time I was 10, I knew better than to call lignite coal. I might get away with calling it soft coal but that was as far as I dared go.
And he was just as picky about what went into our furnace at home. I was expected to set the slate aside in the coal bin under the front porch. It had better not show up blocking the grates!
On a somewhat related note, he got disgusted when someone talked about an "automatic" stoker. He always insisted there was no such thing. Powered, yes; automatic, no.
ChuckAllen, TX
Thank You for the valuable info!Had the Diesels not come, it would be interesting to see how 'Steam' would have evolved.Had not the War not intervened, Mr. D's Machine may well have accomplished it's task much sooner.
QED?
Take Care.
NDGThis type of topic could quickly go from General Interest to OCD, but there must be a limit to size of Boiler, Cylinders and Boiler Pressure where a Dome Throttle would be efficiently used, Superheaters beyond, or not. Those huge articulateds would use much steam, and a dome throttle would have to be of quite a size to do the job. Many Questions, the answers I do not have.
Many Questions, the answers I do not have.
The actual answers are at a bit of a right angle to what you are probably expecting.
A principal reason for implementing a multiple is that instead of throttling a large port, the multiple cammed open a number of ports progressively, each one having relatively good flow. There was also one relatively small port that cracked open 'first' to avoid the problem seen on the British engine, the pressure differential tending to hold the throttle open with unexpected force.
However, as early as 1912 the Germans had a positive and very effective 'dome' answer to most of the issues objectively involved with a dome throttle's steam flow characteristics: the Wagner throttle. This was an early (and quite effective) version of a fluidic amplifier, which used a small shaped plug and passage to control differential pressure across a much larger throttle valve 'in servo'.
The next issue that a large dry pipe and restricted vertical clearance poses is that of water separation at or near the throttle. The multiple 'cheats' at this because it puts the whole length of the dry pipe up to the header and then the whole length of the elements ahead of the throttle's ports, so any water carryover has a better chance of evaporating and then becoming reasonably superheated by the time it would be passing the throttle with sufficient liquid mass to give runaway issues. But it would not be 'impossibly' difficult to use a Wagner throttle there, perhaps acting in much the same way as a conventional dome throttle but well displaced from the point any reduction of overpressure would cause surging and priming into the dry pipe at its mouth.
Big issue with larger pipes is the amount of vertical space inside the shell they occupy, reducing the vertical space between the effective 'mouth' of the dry pipe and the water level ... especially on grades. Porta pointed out that treated water in a boiler resembles boiling milk, with the level surging much more than you might think on the slight pressure release occurring with 'safeties lifting at the away' -- or if a big non-Wagner throttle had to be horsed open and then became difficult to wrestle closed. If you wonder why Woodard put 8000's dry pipe outside (as the Russians did in their lavish vertical loading gage) this helps explain it. You need really good, reasonably high volume steam separation (see the NYC Niagaras for a well-thought-out example) to get the trick to work otherwise.
Again, the key is to have the superheater circuit 'ahead' of the throttle and arrange to circulate steam through the elements (and recondense it as needed to an appropriate point in the Rankine cycle to keep the element temps where they should be). An American Super-Power locomotive will not run away like that for two principal reasons. One is that slugging into the elements is throttled effectively just like any other steam mass flow. The other is that a power reverse gives immediate proportional control over effectively centering the valve (this is not quite the same thing as centering the reverser because of the action of the combination lever) and because a modern locomotive should have long-lap long-travel valves to give quick and positive port opening to steam at speed, you quickly cut off to where even high rotational inertia won't keep the motionwork spinning.
Do not get me started on why the PRR T1 does not have separate trim of the valve gear and the steam circuit -- it is one of the improvements that are easily proposed to improve an unconjugated duplex-drive. Note that it would be very difficult to provide dual throttles -- not that the actuation is a problem, the T1s had very effective air-servo throttles; it's that there is no physical room to 'siamese' two separate sets of ports in the restricted space at that point in the boiler. Redesigning, if you don't care about lumps and bumps in the shape, is not rocket-science packaging, but in my opinion a better approach is simply to provide four smaller Wagner throttles in the four passages to the 'cylinder ends' of the forward engine, and simply adjust those to derate the slipperier engine relative to the rear ... they act with even greater quickness and effective positive location than the valve gear on 3985. (If you have never seen that gear go from full forward to full reverse, you really should; I could not believe it was designed to move that fast if commanded.)
Meanwhile, even in merrie Englande there is a steam 'driver brake' (we would call it the independent and use air) and again it is not rocket science to arrange this so a quick push on an easily accessed 'mushroom shaped button' (familiar perhaps to Citroen drivers) with relatively long travel and increasing positive feedback resistance -- you whack that and the slip is retarded while you start figuring out how to wind the crank or whatever without cracking your jaw or occiput, or have the fireboy drop his sammich and cuppa and help you whack the regulator to a more attenuated state of affairs.
(Better yet is to put a lateral caliper over the main driver and modulate that with your little push button or automatic feed from slip control; it may look a little weird but it will give you an away if there is any way to away... as it were.
Ask Louis Newton about the fun that happened when certain N&W valve gear became unexpectedly subject to higher inertia forces during operation. Pity there were no cell phones or YouTube back then.
Great Data.
Thank You.
Yikes, some film clip! Goes to show not everybody gets it right all the time, not even the Brits. Oh well, mistakes are there to be learned from.
Only the winners of NASCAR races should be doing "burnouts."
NDGO T. Safeties open, Lifting Water on The Away.
Or, Why only an Idiot Puts the Superheater on the Far Side of the Regulator.
Even if you can jam the regulator closed again, on a Black Five doing this, you'll be Blue Petering until (1) all the excess new steam has blown through, or (2) somebody grabs the unwinding reverser handle and cranks it back a good way toward mid. At least the screw reverser handle didn't clock the poor guy on the jaw this time on its way out...
schlimm Firelock76 I cannot speak for all of 5632's excursions, but when I rode behind it mostly in an open gondola, Union Station to White Pines and return, I was grimy, but not too bad. The only time I saw it pouring out dense sooty smoke was for reason #1 ("the head-end crew's hamming it up for the run-by cameras") on that excursion and three other times I was a bystander.
Firelock76
I cannot speak for all of 5632's excursions, but when I rode behind it mostly in an open gondola, Union Station to White Pines and return, I was grimy, but not too bad. The only time I saw it pouring out dense sooty smoke was for reason #1 ("the head-end crew's hamming it up for the run-by cameras") on that excursion and three other times I was a bystander.
The usual reasons are (1) as stated, 'richening' the feed to 'give the fans what they want' (insert comparisons with contemporary diesel-driving children 'rolling coal'); and (2) periodically sanding the flues to clear them of accumulated soot.
When burning heavy oil, not all the fuel combusts, and a combination of liquid gunk and solid carbon particulates adheres to metal surfaces. Preferentially this occurs with gas speed and vector changes, especially at the rear tubeplate, and where active combustion in the gas plume ceases (almost immediately after entering the tubes). This has to be cleaned out fairly regularly or it will build up, inpede both the draft and distribution through the tubes, etc.
It is not practical to do this with steam or air 'soot blowers' due to the boiler geometry, but easy to use refractory grit to 'help it along' -- the cheapest way, throwing in some scoops of sand through the firedoor, also being one of the most effective. A grain of sand liberates many more times its mass worth of soot as it goes through the gas path!
(3) is poor firing, either through lack of knowledge, problems with the equipment, or problems with the fuel. It's less likely to be due to 'quench' from staybolt leaks or other things that evolve steam into the gas plume, but that can happen. Burning off just the hydrogens from the surface of fuel droplets (which are easier to start 'liberating' in combustion) leaves you with black carbon on the outside, which is great for heat uptake but poor if there is anything that will preclude full combustion to at least CO by the time gas temperature and "illumination" go down below minimum temperature for carbon to react quickly enough with available oxygen. What's left goes out just as residual particles do with coal firing...
Firelock76This discussion of oil firing reminds me of something. I've seen some excursion footage of Burlington 5632 in the early '60s. There's some shots of the locomotive belching out a heavy black smokescreen, thick enough to turn a World War Two "Fletcher" class destroyer green with envy! "Well," I said to myself, "there could be several things going on here. Either the head-end crew's hamming it up for the run-by cameras, OR they've got an incredibly bad load of fuel oil, OR that engine's in dire need of servicing, OR the fireboy's got no idea of what he's doing!"
C&NW, CA&E, MILW, CGW and IC fan
I think the general consensus concerning the previous owners of Reading 2100 and their abortive oil-firing conversion is they'd bitten off more than they could chew and really didn't know what the hell they'd gotten themselves into.
'Nuff said there, hopefully the locomotive's in much more capable hands now.
This discussion of oil firing reminds me of something. I've seen some excursion footage of Burlington 5632 in the early '60s. There's some shots of the locomotive belching out a heavy black smokescreen, thick enough to turn a World War Two "Fletcher" class destroyer green with envy! "Well," I said to myself, "there could be several things going on here. Either the head-end crew's hamming it up for the run-by cameras, OR they've got an incredibly bad load of fuel oil, OR that engine's in dire need of servicing, OR the fireboy's got no idea of what he's doing!"
Or maybe all four?
Firelock76Not trying to start an argument but I thought I'd bring that up.
Note that this is the reason I have qualifying words like "some" and "often" in there.
The design of the burner and nozzle, the steam or mechanical pressure used, the arrangement for primary and secondary air, and the skill and knowledge of the fireman and engineer are all part of the situation. Note that the Frisco 1522 crew also reported that it easily made the transition from heavy to light oil firing with little difficulty. But there are plenty of disastrous attempts at implementing light oil firing in situations where a simple von Boden-Ingles burner (either forward or rear-firing) would produce a fine luminous plume using little more than properly-adjusted steam. And there are also no few conversions where 'wisdom' in the ways of industrial #2 oil firing have NOT translated well to locomotives, Reading 2100 being an interesting case in point (which was partially, but not completely, re-engineered but never quite 'fixed').
Somewhat off-topic:
My dad once rode an excursion around the 1970's on the E-L in Ohio behind a RDG T-1. I think it was 2102. They were burning some very bad coal, which was quickly depleted. They actually picked up some pieces of discarded ties and tried to burn those, but it was futile and the engine and train had to be towed in.
My dad had been in the coal business many years before. He did a "railfan inspection" of the engine before departure, and expressed his misgivings about the coal. The people he talked to dismissed him as a foolish old man. They seemed to think "Coal is coal". My dad would say "bad coal is dirt; good coal is fuel".
Tom
Wood worked well in locomotives that were designed for it, like those cool 19th Century steamers we all know and love so well, or at least that I do.
Wood did have some advantages, being easily ignited and burning clean with little ash remaining to dispose of. Disadvantages, not as many BTU's as coal or oil, and sparks, lots of 'em, which lead to those "balloon" smokestacks.
Matter of fact, the Tavares, Eustis and Gulf Railroad in Florida runs their 2-6-0 on wood fuel, which makes sense. There's no coal in Florida, and there's plenty of scrap lumber available which is cheaper than using oil.
Interesting Overmod's comment about oil burners only working well with bunker oils. When Canadian Pacific had a steam program with Hudson 2816 they switched from bunker oil to waste oil in 2002, bunker oil being hard to find anywhere on the system except for the Pacific Coast. Then one day in 2003 the fuel truck didn't show up so they filled it with diesel fuel. They had no problems and never looked back. Bill Stetler, then in charge of the program said "The engine doesn't care what it's burning. We were worried about the viscosity but the BTU's are there." Of course, CP doesn't have a steam program (at the moment) so it's all a moot point anyway.
Not trying to start an argument but I thought I'd bring that up.
The locomotive firebox was designed to burn the particular coal available to the railroad. Like anything else you get optimum performance when everything is designed to work together. Anthracite and bituminous coals burn very differently. They require a different type of fire. A Lackawanna locomotive burning anthracite had a very different firebox from a bituminous burning locomotive. A steam locomotive can burn anything that provides sufficient heat to boil water. Of course, wood does not generate the heat that coal or oil provide.
This is a rather complicated subject, made even more complicated because some locomotives were convertible between fuels, and some were made to work on dual or multiple fuels.
Locomotives burning hard coal could usually be fired on bituminous (with a different technique and some additional care), but the opposite was not generally true. (See Angus Sinclair's Development of the Locomotive Engine and the online references on the Wootten firebox that were posted a few days ago for more details)
Many engines built as oil burners were only set up to be fired on their 'design fuel' -- usually #5 or #6 'bunker' fuel oil. There are often problems firing a locomotive designed for this fuel on 'lighter oil' (particularly #2 diesel or home heating oil, and especially 'winterized' diesel or #1 that includes kerosene fractions)
A wide variety of potential conversions to oil were drawn up and, in some cases, parts fabricated during the mine strikes in the late '40s. I believe there are good drawings for both the J and A classes, the latter having a certain more-than-academic appeal...
The quality of bituminous coal could have a significant effect on locomotive performance, both in terms of heat release and ash characteristics. Too many variables for a short post. Same was true of coal quality -- the AAR put on an extensive promotion in the late '40s and very early '50s for railroads to use washed 2" coal with few 'mine run' adulterants. One of the great advantages of 'late' wide-firebox designs with FireBar grates was that a wide variety of relatively poor coals could be cost-effectively burned and good steaming maintained (without the fireman either being a one-armed paperhanger or a refugee from a minstrel show).
There are a couple of problems with firewood as a locomotive fuel, especially the 'good' kind (like fatwood). It ignites readily when properly seasoned, burns initially very hot, but does not last long, and delivering it precisely to a firegrate at locomotive-firing temperature and draft is not simple. It would be comparatively difficult to fire a Big Boy with it unless you ground it up and fed it in as chunks -- with a great many of the chunks 'levitating' much as the subbituminous did. And you would need proportionally larger tender capacity... or face perhaps dramatically smaller range ... and be prepared to handle heroic amounts of ash either in the ashpan or at the front end.
(Oh yes, that begs the real problem with running a Big Boy on firewood -- where you would cost-effectively expect to find that firewood in the required quantity where the Big Boys ran!
How particular were steam locomotives about the fuel they required? Could a locomotive burn any kind of coal or were certain types of coal required depending on the design of the locomotive fire box? For that matter could one make a Big Boy run on firewood?
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