Hi,

Just out of curiosity, has anyone used a steam generator to power a fireless cooker?

Doug vV

In short, it doesn't work.

Steam generators are designed to produce quantities of low-pressure steam as heat transfer, typically at low pressure and temperature.

Fireless locos need large quantities of superheated water at extremely high pressures (think 600-800 PSI) and temperatures (300 degrees or so, made possible by the higher pressure) to function. This requires huge industrial boilers, not portable, temporary ones.

It would be like trying to move an auto with no fuel line by spraying starting fluid into the carburetor, assuming you had one with a carb. you'll get a couple cylinder strokes, max.

Generally correct, but it should be noted that very few US fireless locos were built for pressures that high. Most of them stored water/steam at more modest pressures, typically 150 to 250 psi. The pressure in the tank was not that used by the cylinders however. The reason fireless locos have comparatively large cylinders is that the design always included a pressure regulator to drop the tank pressure to a lower value. Porter generally used 60 psi in the cylinders. This practice kept the tractive effort somewhat constant while the supply of superheated water became steam. There would be some drop in T.E. once the water got low, but for most of a working session it stayed in a usable range.

Hi,

I was wondering if steam from the steam boiler could be piped directly into the cyliders and by-passing the boiler. At 60 psi, it sounds possible but not probable. Sort of like running a GG1 on a F unit B unit's electrical by rewiring the electronics.

Thanks.

I was also wondering if anyone tried it. I would not be surprised if some goofs may have tried it.

Doug vV

Seems like it would be more feasible to run one using air from a compressor. The large gas powered ones put out some pretty good pressure and volume. Might be enough to either charge the tank or go directly to the cylinders and chuff around the yard a bit.

You'd need to do some calculations or experimentation, and also come up with a method of providing lubrication, but it might work. I know we once moved a Heisler out of the shop on house air. Charged it up to 150 PSI or whatever the most we could make was, and then opened the throttle. Got about 4 or 5 good chuffs, and then it diminished rapidly, but it was enough to move her an engine length or so, which was all we needed.

A boiler is a vast reservoir of potential energy, stored in water being converted to steam and expanding many times in volume as a result. LPG tanks work the same way, as do compressed oxygen/helium tanks.

Compressed air simply runs out. If you simply use compressed air, you will deplete the stored potential energy VERY quickly as the pressure drops that quickly. This technique has been used on a fireless at the Lake Shore Railway Museum in North East, Pa., and at best they can get a back-and-forth run or two out of it before it runs out, with a LOT of coasting.

It has been tried before. Stories about the early days of IRM at the Chicago Hardware Foundry relate that the owner, Frank Sherwin, had a large compressor he rigged up to a small steam switcher (possibly Com Ed 7, a 0-6-0T still at IRM) that he wanted to use as a plant switcher. Stories have it, it would run about a hundred feet, then had to stop to build pressure again.

Seems to be a growing amount of bad information out there on fireless cookers. A search of the RyPN archives will turn up some facts, many of which I provided having owned a 7 ton Porter fireless, Apache #6, for some number of years. So, the facts would be:

* As originally built, the #6 was charged with hot water and steam to 150 psi. This would power it for about 3 hours or so before running back for a recharge when it reached 50psi. So, figure 3-4 hours on a charge of steam at 150psi.

* We ran the #6 on air. We would charge it to 100 psi and it would be good for about a half hour of running. That’s the difference between the stored energy of steam versus air.

* Even on air, it ran fine on 5psi. Its a volume issue. Not fast, but it would move along nicely.

As to using a portable steam generator, I’d doubt a steam cleaner kind of generator would work, but worth looking into. However, a portable boiler does indeed have potential. Keep in mind the tank on a fireless is large in order to store the energy to move the engine with no heat source for several hours. A decent sized portable boiler would probably not work for charging the tank. Again, volume at a consistent pressure being the issue. However, using the portable boiler, and its heat source, should be enough to operate the locomotive. Again, high pressure at the piston is generally not needed. And the expansion of steam makes up for volume. Anyone who has run a steam locomotive will tell you that its rare that the throttle is fully opened.

If anyone has specific questions and would like to discuss it, feel free to send me a private message. I'd be happy to help, but a towed steam boiler probably would indeed work out.

J.R. May

I believe that the folks at the Nevada County Narrow Gauge Museum (Nevada City, CA.) actually built a replica 0-4-0T that is powered by a steam generator. Their yard is only about 100 yards or so, so maybe that is why it works for them.

I took the question to mean sending steam generator steam to the engine and not using the insulated tank at all. You might want an insulated receiver (tank) to act as a buffer for cylinder events but that's all. I don't know whether it would work but it should not be that difficult to work up the numbers based on steam consumption of a particular engine at various speeds and cut-offs and compare that with the output of various steam generators. These are usually given in pounds per hour so one would need to convert that into steam volumes.

The Vapor OK-4625 could do 3000 lbs / hr. at 200 psig (388°F). That's 360 gallons. What sort of water consumption would you expect on, say, a little conventionally-fired industrial 0-4-0 puttering around and taking visitors on rides? Seems like it might work. The consumption vs. SG firing rate might be the biggest issue. Maybe using the whole tank isn't such a bad idea after all.

some quick checks reveal there are high pressure steam generators available. You could mount one on something of a tender or boxcar whatever and feed steam to the cooker.

I don't know why you would want to bypass the boiler when there are other operating apparatus tied to working the cooker.

I had looked at by-passing the original tank to avoid required state inspections. Here in NJ the boiler I had planned to use would have been a code boiler and trying to using the original tank would have been a huge headache inspection wise. The idea was to try the boiler and really see how things worked out, learn from it as to performance and such. My partner on the Porter preferred to run it on air as it was simpler and quicker, but I am a true steam guy. Plus, we had a limited water supply which would have hindered how often it could be run on steam.

All in all, running on air for a small engine was just fine on our short track. We were building a compressor car, but my partner on the project died suddenly at home and that was the end of the project. I sold the locomotive off.

J.R. May

Perhaps I am just a "Nervous Nelly", but I suspect that there are a bunch of things that need attention before such an idea were put in place.

Before I would try this, I would want to consult carefully with the "high pressure steam generator" manufacturer to ensure that such a boiler was appropriate to the task. Such devices aren't necessarily "rated" for such service; use such a device in a non-standard application at your own risk!

I am under the impression that the average "stationary" boiler is designed a bit differently than the average "locomotive" boiler. I understand (perhaps incorrectly) that this is, in part, because a locomotive must withstand the environment of jarring movement across frogs and poorly tamped jointed rail, and partly because of the unpredictability of the "load". Probably a bunch of other things too. Solution? Talk with the manufacturer. Perhaps get a custom design which is more suited to the rigors of the desired application.

I would worry about the "crown sheet" or its equivalent: Is the steam generator's crown sheet at risk when the tender or other car sways as it travels? When the train is braking? When accelerating? When slack runs in or out? Solution? Perhaps run the water level higher than would normally be done for that boiler. What about steam space? Perhaps buy a bigger unit and de-rate its output because of the smaller steam space. Talk with the manufacturer!

How does one "plumb" such a high-pressure steam line to the locomotive? What happens if the train parts, between the locomotive and the car holding the boiler? There would need to be fail-safes for this issue! Perhaps the car would need a rigid drawbar and safety bars instead of a Janey-style coupler.

How does the locomotive fireman tend the water level if the steam generator is in a separate car? Perhaps an additional fireman is needed to tend the "high pressure steam generator".

I'm sure that these issues could be solved, along with all the other "little things" that pop up when attempting to realize such a "what if" idea.

Regards,
Bob Milhaupt

Hi,



I guess it depends how high pressure is defined. Others have already said the cylinders on a fireless cooker have a pressure of 50-150 PSI. Not high pressure in my opinion. Regular steamers had up to 300 PSI.

As for how to pipe it, articulateds have been around for over 100 years and have worked with over 200 PSI. N&W 1218 and UP 3965 are but two that have operated fairly recently (post dieselization). How about the accordian AT&SF articulateds?

Not trying to belittle the statement but it's been done and the starting point is a known technology. Care in the design of the feed pipes would be needed.

Best for operation would be to have a stationary boiler and use it to charge the cooker. If that is not possible, then maybe there are other ways. Just like a GG1 should be run on overhead but with that no longer available, what about ...... fill in the blank ...... as a power source?

I was just interested how far some had explored the possibility of alternate steam sources for fireless cookers.

Doug vV

Let's start by going back to thinking of steam power as heat, not pressure for a moment. Note that you do not charge a fireless cooker by piping high-pressure steam into it; you charge it by raising the temperature of the water until the equilibrium pressure of the water mass -- and it may stratify a bit but not so much when the locomotive moves a while -- comes up to the desired "starting pressure".

We can clearly start charging by using cleaply-heated DHW, then bring equilibrium temperature up to the equivalent of whatever cheap low-pressure (e.g. heating boiler, 15-30psi) boiler you run. There will be a limit to how much heat you can inject because the back pressure of the heated critical water will eventually balance that of the steam and rather obviously mass transfer will cease. At this point you could change over to your high-pressure system to add the additional heat needed to get the water mass up to its starting equilibrium pressure; note how much less flow is involved in this vs. charging the whole way up using an exotic and somewhat dangerous machine for the whole thing (as would be done for cheapness when a fireless cooker was charged on house or process steam lavishly generated for a whole facility's average or peak need)

The California Solar Steam Train serves as an example of h as ow this might be done: you have several different types of solar concentrator and nhot-water storage, and when charging or 'boosting up' the locomotive you use the appropriate-temperature source at the appropriate time (or run in parallel, dropping systems as each reaches its practical max pressure). Think of the reservooir on the cooker as a battery and you will see something else: charging a long time from a small high-pressure source gets the same net enthalpy as a fast high-volume charge ... and the rate at which the cooker powers the cylinders through the reducing valve is not a function of what the charging rate was.

A Vapor SG is a fairly sophisticated steam generator; it'd just not something that handles the wide swings and relative inefficiency of typical small and primitive steam running gear effectively. Stands to reason that something like a small Lamont boiler would be even better than an obligatory once-through, since circulation can be varied independent of actual water throughput -- you circulate fast at lower pressure, then bubble the steam up from the bottom to get the quickest "open-type" heat exchange.

As with a fireless, the only 'open' steam supply is the charging line, and is difficult to see how with blue-flg protection operation you could have an accidental full separation or break there without stop valves tripping on the higher mass flow.

And yes, you can build a higher-pressure light oil fired SG and use it, like the genset in a full-parallel hybrid, to trickle-charge the boiler continuously, whi the steam demand in practice is likely to be asynchronous evenon a seemingly flat railroad with little fast acceleration or high speed. Yes, you could have a reasonably high-pressure truck-mounted system and run it to an engine 'in distress' for a relatively quick 'dose' if ignorance drops the pressure too far.

I did considerable work on what would be involved in the 'next step' beyond effective water treatment (e.g. TIA or Porta-McMahon) - where you have to blow down and charge boilers that should be kept hot amd pressurized for decrease strains. You can't just drain, you need to pressurize with an inert gas to keep from flashing, then use a physical pump like the circ pump on a LaMont to move the boiler water to where it can be filtered, deoxygenated, etc. I suspect that a few inches of even "homemade" aerogel and some shields can make a tank lose relatively little heat in even vastly longer time than a boiler or reservoir with good but thin lagging can manage.

So I see no particular reason why you couldn't charge enough water from a variety of sources 'overnight' to get a few hours of work, or even put some form of SG in as 'genset' charging.