Per Blue Streaks comment:
A cab-forward wouldn’t necessarily have to be an oil burner. The Germans built some cab-forward coal burners in the years prior to World War Two. However, the engineer and fireman were separated, the firebox being in the back of the boiler by the tender. How’d that work out as far as co-ordination of effort was concerned? I don’t know. Possibly not too well, German steam that survived into the sixties seemed to be of conventional layout.
The information I have (for example Gottwaldt, Streamlined locomotives of the Reichsbahn, p.33, showing the ‘Kohlenstaub-Sonderbauart’ [the specific/special design for pulverized coal] on 05 003) shows the boiler ‘back-to-front’ with the firebox adjacent to the cab (and both crewmen together) just as expected. The little door at the ‘rear’ of the shroud is access to the air compressors, smokebox door, etc., not access fo a ‘power compartment’ as on N&W TE-1 or Bulleid’s Leader.
Juniatha will have full mechanical details of how the burner and windbox were arranged; from what I can tell, the feed was from the throat of the firebox (as with some oil-burning practice) but the ‘burner’ is shown extending the length of the firebox sides. I’d suspect that some version of forced draft via the ‘Luftkanal’ was supplied, in addition to the more normal induced draft via the stack and whatever overpressure came in by way of the entrained hot air in the fuel mixture.
If I understand the setup correctly, the coal supply runs pressurized. A turbine air compressor and air preheater supply hot compressed air to a stoker-like feedscrew, with the coal dust then becoming entrained in the air stream in a mixing chamber – this was then blown to the burner, the mixture comprising much of the primary air and the fuel together… this would not bode well for leaks, although I’d expect the thermal mass of the arch would keep things lit short of a need for explosion doors. At least I’d hope so.
My suspicion is that if all else worked as expected, the violently explosive nature of pre-ground coal dust, and its propensity to stick or ‘bridge’ with even small levels of humidi
Why would you need a stoker that goes all the way to the cab?
With modern automated equipment the fireman can monitor the firebox and operate the stoker remotely from the front of the locomotive.
That was how the American Coal Enterprise ACE-3000 (and related proposals) was designed to operate;
https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US4425763.pdf
The German innovation’s description causes me to ponder:
Did they reinvent the Camelback, the Mother Hubbard, countless Anthracite burners?..rarely called saddlebacks…that isolated the fireman at the rear and could have been designed to put the cab further forward.
Thanks for the comments that included the ACE3000 pics.
I think the article included another, different, interpretation of the ACE in concept art.
I haven’t had a chance to read all replies, could it be fired with natural gas or ethanol? I’m not an engineer, I’m just tossing out a few ideas.
It could, but it probably shouldn’t be. Ethanol is excessively expensive and has some chemical drawbacks as an external-combustion fuel (some of these are the same characteristics that make it a good racing fuel). It’s also relatively lacking in heat content compared to liquids of equivalent volume that have more carbon.
Natural gas has a very low heat content both by mass and by volume. You can go with CNG, in which case you have pressure issues, or you can go with LNG, in which case you have refrigeration and condensate issues. The situation is not at all like diesel fuel, where you can essentially slop the stuff around in buckets and not worry excessively about flashpoints, critical-mixture explosions in ambient air, and other more or less nasty things natural gas firing not done via fully sealed pipework can provide for you.
Where ethanol – and methanol, which is easily made from methane – shine, in potential, is in direct-steam cycles, for example the approach taken by Oxford Catalytics to generate reasonably-superheated steam directlly from catalyzed reaction of fuel with about 30% hydrogen peroxide. I don’t expect to see direct steam cycles deployed on locomotives any time soon!
RME
[quote user=“Overmod”]
The information I have (for example Gottwaldt, Streamlined locomotives of the Reichsbahn, p.33, showing the ‘Kohlenstaub-Sonderbauart’ [the specific/special design for pulverized coal] on 05 003) shows the boiler ‘back-to-front’ with the firebox adjacent to the cab (and both crewmen together) just as expected. The little door at the ‘rear’ of the shroud is access to the air compressors, smokebox door, etc., not access fo a ‘power compartment’ as on N&W TE-1 or Bulleid’s Leader.
Juniatha will have full mechanical details of how the burner and windbox were arranged; from what I can tell, the feed was from the throat of the firebox (as with some oil-burning practice) but the ‘burner’ is shown extending the length of the firebox sides. I’d suspect that some version of forced draft via the ‘Luftkanal’ was supplied, in addition to the more normal induced draft via the stack and whatever overpressure came in by way of the entrained hot air in the fuel mixture.
If I understand the setup correctly, the coal supply runs pressurized. A turbine air compressor and air preheater supply hot compressed air to a stoker-like feedscrew, with the coal dust then becoming entrained in the air stream in a mixing chamber – this was then blown to the burner, the mixture comprising much of the primary air and the fuel together… this would not bode well for leaks, although I’d expect the thermal mass of the arch would keep things lit short of a need for explosion doors. At least I’d hope so.
My suspicion is that if all else worked as expected, the violently explosive nature of pre-ground coal dust, and its propensity to stick or 'brid
The ACE3000 designers included many of the major proponents of modern steam including Livio Porta and David Wardale.
They designed the locomotive to use modern automated coal handling and combustion chamber/boiler systems based on then current practice in the power generation industry.
If you read the patent I cited in my earlier post it explains why the firebox setup would not require the fireman to handle the same tasks as on earlier coal fired steamers.
Note I am not saying that the ACE3000 would have been able to successfully complete with diesels but I do think it would have been able to operate as designed.
The railroad industry doesn’t seem to agree with you about LNG/CNG fuel as they are pressing ahead to develop the technology given Natural Gas’s current price advantages vs. diesel.
Whether the effort goes any farther than Burlington Northern and UP’s similar experiments back in the early-to-mid 1990’s remains to be seen.
The main reason not to use the fuels mentioned in a steam engine is that internal combustion engines burn them much more efficiently.
The Oxford Cat
I was talking strictly about external-combustion locomotives.
There have been various efforts to develop CNG locomotives for quite some time (remember RailPower’s CINGL development?) but only recently (with the gas glut from fracking) has the economics come together. LNG is technically more complex in some respects (here is a Railway Age article that’s a good introduction to the subject), and some recent technical advances have made it far more practical. But these largely remain systems with IC engines (combustion turbines or piston engines) and comparatively few even use or propose Rankine-cycle bottoming even though there are comparatively mature systems to do that.
Your point about burning ‘much more efficiently’ is accurate and correct… and it probably is fair to add that NG fueling can produce “cleaner” exhaust than diesel, with considerably less fancy (and expensive, and economy-reducing, etc.) aftertreatment systems. Clean air was at one time the significant salient advantage for natural-gas locomotives, IIRC.
,
Here is a link to a good article that describes the basic Oxford Catalysts approach.(If you are interested in the subject, download the full article.)
Note that there are other approaches that utilize both catalytic decomposition of H2O2 to ‘direct steam’ and the use of ;combustion’ fuel/H2O2 to produce steam. A key differentiation is that the Oxford Catalysts team understood early that modulating the average num
Well the reality is steam is totaly impractical. Energy Is lost converting water to steam and more energy is lost converting steam to power. Internal combustion eliminates the steam step making it more efficient on the power side and the exhaust polution side. Steam can’t win in any way.
Well yeah, we know all that, but this is just fun speculation. No harm in that.
Kind of like speculation on “what if General Robert E. Lee had an atomic bomb at Gettysburg?”
“Gen’ral Lee, we’re losin’ sir! What’re we gonna do?”
“NUKE 'EM!”
The Rankine (steam power) cycle, with some tweaks such as a feedwater heater, is pretty close to a Carnot cycle. The Carnot cycle is the theoretical highest efficiency – subject to a limit on the “hot side” temperature and the “cold side” temperature of the thermodynamic cycle.
The Brayton (gas turbine) cycle is also a pretty close approximation to a Carnot cycle. One key difference with the Rankine cycle is that there is no phase change – the raising steam from water you talk about. This means that considerable mechanical shaft power from the turbine has to be recycled into running the compressor, to boost the air working fluid in pressure so that heat can be transferred to it at a higher temperature than heat is rejected at the turbine exhaust.
Gas turbine engines live or die on the mechanical/aerodynamic efficiencies of turbines and compressors. This also explains why gas turbine efficiency drops off so dramatically at part load – as you drop the RPM’s on the turbine and compressor, their efficiency as well as pressure ratio drops off.
The steam engine (Rankine cycle) only needs to move a much denser fluid – liquid water – from atmospheric pressure in the tender up to boiler pressure. This needs much, much less mechanical power than a gas turbine compressor, whether the water is “injected” into the boiler using a mechanical pump or using a steam-ejector pump (the common type of steam locomotive “injector”). The “supercritical” steam cycles used in some of the latest electric power plants is sorta halfway between a R
This nothing like speculating on “what if General Lee” had an atomic bomb. This is like speculating on “what if China develops their missile tech to the point that our Carrier Battle Group Navy is rendered obsolete – what do we do now?”
It may not be in 10 years, in may not be in our lifetimes, and it may not be in a 100 years, but at some point, we are going to run out of economic oil. You live-steam hobbyists, you people exhibiting steam traction engines at shows, all of you operating steam locomotive railroad excursions, all of you arm-chair engineers speculatin’ away on trains.com, keep doing what you are doing, because there may come a time when knowing how to build, maintain, and operate steam locomotives will become essential.
But at what point are we going to run out of economic natural gas? Hint: a LOT longer than the oil reserves…
The one scenario where I could imagine some type of steam technology being used for railroad traction would be utilizing solid biomass fuel but it’s hard to picture that taking the place of fossil fuels.
As f
You did not read the references for Oxford Catalysts very carefully. ;-}
It is not difficult to determine the marginal cost for a barrel of syndiesel (or equivalent) prepared via Fischer-Tropsch either from gasified coal or natural gas. It is not difficult to determine the marginal-price range for great extension of the various biodiesel processes – specifically including algae, which is the only generation technique that does not need to follow Malthusian proportions.
In brief, we are never going to ‘run out of oil’ as long as there is a cost-effective demand for it, even if as a carrier fuel. There are too many advantages, including the ease of distribution and storage.
It probably won’t, except for political or witch-hunt reasons. Some of the ‘biomass’ contenders, notably the torrefied fuels, are primarily intended to work as additives for reasonably clean coal combustion – economics (including, if you must, ‘welfare economics’) will determine the operant proportion of biomass above that which produces all the desired effects from the ‘additive’ components.
I am working on a multifuel system that is essentially a throwback to the very early days of oil firing on locomotives. This uses a GPCS-compatible bed of mixed coal and biofuel, providing baseline output, with some combination of liquid and gas fuel (as needed) through separa
Relax Paul, I’m just trying to make a joke here.
Honestly, no-one would be more happy than me to see steam come back, in whatever form. Maybe it’s possible, maybe it’s not. Probably not.
Keep in mind a whole industry that no longer exists would have to be re-created from scratch. It’s all gone! Baldwin, ALCO, Lima, all of them. The manufacturing equipment was scrapped a long time ago, the men that built the locomotives are dust, or the very few that are left soon will be, and all the appliance makers are gone too. All that remains are the blueprints.
There’s a much better chance of wholesale mainline electrification where feasable than there is a return to steam. Or another power source may be waiting in the wings for some genius to find it or for God to reveal it in His own good time.
But steam? Man I LOVE steam, and I think the world changed for the worse when steam died, but it ain’t gonna happen. More’s the pity.
Hence my statement that this thread is all fun speculation.
Paul,
A couple of quick comments on the Rankine cycle.
One larger contributor to efficiency is that liquid water is nearly incompressible, so pumps can be made to be very efficient. Gas based cycles have to contend with the gas heating when compressed, which provides all sorts of ways for the entropy to increase.
One limit on maximum steam temperature is that the fraction of water that breaks into H+ and OH- increases with temperature. 1200F appears to be the practical limit for steam temperature in order to keep corrosion under control.
Any locomotive that would be designed today using steam, would look nothing like the steam engines that the diesels phased out. The maintenance cycle would have to be such that other than putting in fuel and steamable fluids (if not a closed loop system) there would be no need for maintenance other than replacing brake shoes and adding sand for the 92 day inspection cycle. Anything more maintenance intensive is a not-starter.
