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Discussion Starter · #1 ·
I became aware of this little project going on out in Cali about two years ago. I had serious reservations about it then, and nothing I've heard since has made me feel much, if any, better about it. :confused:

The project in question is a scratchbuilt locomotive...in 3 foot gauge. It will use a lot of fabricated and non-standard parts including a package "steam generator" (read: watertube flash steam boiler) to try to get around some of the National Board/FRA requirements.

Pictures and description can be found here:
http://www.ncngrrmuseum.org/pb/wp_5031ec94.html
http://www.ncngrrmuseum.org/pb/wp_6d26f903.html
http://www.ncngrrmuseum.org/pb/wp_1da4e4fe.html
http://www.ncngrrmuseum.org/pb/wp_64151ef1.html

Some of the questions that have been raised by myself and (many) others, but not publicly addressed by the group in question are (in no particular order):
1. Won't the side loading from lack of crosshead guides cause the piston rods to bend? Or at least lead to premature failure of the packing glands?
2. Are the siderods adequately sized for the stresses involved?
3. Will the brass fittings used in the cylinder fabrication provide adequate (and safe) steam passages?
4. Will the box frame be adequately rigid? Won't the lack of adjustability (wedges, etc) increase wear and compromise safety?
5. Will the flash steam boiler be properly sized to match the cylinders, what calculations were used, and how do they plan to ensure it's safety?

Since the public will eventually be hauled by this thing, a lot of other groups are watching-- because should it fail and result in someone getting injured the insurance people may assume that those other groups are just "grown men playing choo-choo" as well.
 

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If they can use a flash boiler successfully, that would be a real boon to rail museums and tourist lines looking to add steam to their roster.

I have to admit, if I had the room, this is exactly what I would be doing, a full size NG steamer, I've often wondered: if you have the room for a 12" guage ride on Mikado engine, you have room for a full size 0-4-0 Porter on maybe 15 or 18" gauge, maybe even 20 or 24" gauge. THAT would be far more appealing to me!

Thats actaully MY dream RR, 24" gauge, with an 0-4-0 Porter in one stall of the engine house, and a Darjeeling B class in the other...why not? if Ward Kimball could do it...
 

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Mike,

I am no steam expert, but am a ME.

Looking at their design, and the project as shown, I am not sure that they have installed everything. The pictures do not show cross head guides, but does that mean they aren't planned? It may be that the group is trying to show how far along they are by connecting things. I think it is easier to raise money if you can show someone something, even if incomplete. The tubing is stainless, and stainless fittings can be a real bear to work with. Brass fittings and hardware are easier, but will probably require more frequent tightening.

I don't have a clue about the proposed boiler. It sounds like it is a self contained unit, and from the look of the insulation inside the firebox, it must be pretty small. 135 psig seems about right for a regular steam locomotive of this size.

Why not pose this question over on one of the 1:1 boards, like RYPN or trainorders?

I think that the FRA will be inspecting this locomotive prior to it running and pulling people. Also, I tend to think that the guys doing the work don't want to see anyone get hurt, either.
 

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I am not a Mechanical Engineer -but I have spent a considerable portion of my life watching them both in pieces and as designs on the drawing table...

Q1: There have been several designers who have never used crosshead guides -Goldsdorf is an example. They are more used to dampen vibration at higher speeds.
Q2: If they are cut from 1 inch steel plate as stated, then they should have a loading of 1 ton per sq inch.
Q3: Brass is fine as long as it is steam that is being pushed through it.
Q4: From the looks of it -it is far stronger then the original Vulcan plate frame that the wheels came from.
Q5: It looks like a "Whyte" flash boiler design -these were used on the "Stanley Steamer" motor cars. The small bore of the tubing is actually stronger than that of a large boiler.

The normal design ratio is 100sq inches of heating area per cubic inch of water boiled per 100 pounds pressure per minute.

I imagine, (because this is how I would do it), the waste gasses from the boiler go through a heat exchanger to the main water tank, (which I assume masquerades as the "boiler").

regards

ralph
 

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Discussion Starter · #6 ·
Mike,
1. The pictures do not show cross head guides, but does that mean they aren't planned?
Answer to #1... There are no "ears" or "shoes" on the crosshead to attach a guide to. This part has been pictured this way for about 15-18 months. Rather a long time for a "temporary" assembly.

2.Brass fittings and hardware are easier, but will probably require more frequent tightening.
Answer or further question to #2... I have been told that common yellow brass fittings are frowned upon in steam installations because the brass gets more brittle at elevated temperatures. Bronze yes, brass no...this info came from our handy dandy local boiler inspector out in the wilds of Pa....maybe materials behave differently on that coast? There is also concerns that they are too small for the cylinder (not a safety problem, just means it won't run worth a hoot)

3. Why not pose this question over on one of the 1:1 boards, like RYPN or trainorders?
Answer to #3...Actually this thing WAS discussed on the interchange recently. They are asking the same questions I've been asking for a long time.

4. I think that the FRA will be inspecting this locomotive prior to it running and pulling people.
Answer to #4... Since their track is insular, it is a FRA grey area. I have been told they are trying to get this thing to fly under the Cali boiler code (which, as I understand, is only concerned about the safety of the pressure vessel proper)

5. Also, I tend to think that the guys doing the work don't want to see anyone get hurt, either.

Answer to #5...The following is from a note from someone who used to be active with the group who asked me not to use his name:

"I still stay in some contact with the NCNG museum as I work literally around the corner from it now. The locomotive HAS moved under its own "power", although I believe they were using compressed air and not the steam generator yet. I will say this, I try not to be publicly critical of the project as I do still have many acquaintances up there, but to be honest those of us with our heads screwed on know that this thing is going to be a massive failure. The initial idea for the locomotive cropped up around the time Hal Wilmunder's Porter was stored up there. Since Les Wilmunder was letting the Porter stay and was going to supposedly allow museum members and others to operate it on special occasions. There was some conflicts of interest between Les and the group resulting in Les and his equipment leaving, yes including the equipment Hal had willed to the group. Around this same time the museum was in a power change as the old president of the group retired and passed on the torch, as this was happening Ken Yeo stopped volunteering his time and took his collection of artifacts out of the museum again because of a conflict of interest.

After the new president and head of restoration were chosen (keep in mind there was no one left qualified to do either of these jobs) the project to build the little faux Porter were started. Why? Well its simple, when the group ran off Les they decided that they didn't need his Porter they could and would build their own. One member put up a large portion of funds since this was his design and more money has been raised since then. Ever since the power shift the restoration group's focus has been heavily skewed towards toys. The railbus at first was a neat idea but it was poorly executed by folks who thought they could make their changes to design to make it safer. While the bus might seem safer, it certainly is not and is operated by folks who have never operated in any form of tourist or railroad service save 1 volunteer. This was the case in Carson City, NV a few years back when the railbus was taken "on tour" and split a switch on the museum grounds because their operators disregard for safety. I have been told by a couple sources that they will NOT be invited back.

Eventually things got so bad that a number of us stopped even bothering to go around. Personally I do still keep some contact with the curator and the folks inside the display building. Thankfully the curator has a good head on his shoulders, but his focus is on the display building and the history he does not make decisions of restoration matters. The NCNG group is a very home brewed group there is no real objective, no goal, other than to the majority of the group's desire to make a tidy little NCNG display train,... There is no accountability, no higher person to raise a fuss with. Someone with political sway might be able to get the City to turn some screws but for all intents and purposes the group is funded by donation, they do not write for grants or recieve any assistance other than the city footing the bill for the power/water.

The NCNG group had much potential years ago but as people got into positions of power they were able to turn the museum from a functional workshop that preserved history into a Coffee Club for volunteers to bs and waste money on pet projects while true historic artifacts continue to rot....."

If even HALF of what my friend said is true, it raises enough red flags in my mind to look like a communist party rally.
 

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Mike,

Ok, that's more info to shed some doubt on the project. I thought I saw some threaded holes on the cylinders that could serve as mounting areas for a crosshead. I haven't looked at this project at all, and those were merely my first impressions.

Certainly, politics surrounding this project have had an effect, but we're really only getting one side, right? Without the technical drawings and predicted operating conditions, it is difficult to predict if this thing will work. What is the required drawbar horsepower they are trying to attain? That will dictate the required torque, which should be translated in to a force, corresponding to the cylinder area/operating pressure. 135 psi across a working area of say 6" diameter cylinders (minus the piston, not the piston appears to travel on both sides, resulting in balanced force in the working direction) gives an approximate 3540 lbs of force to be translated in to a torque at the wheels (assuming a piston diameter of 1"). I don't have time to calculate the TE, but I imagine it would be pretty small, maybe able to pull 2-3 short cars.

These guys appear to be trying a novel approach to building an operating steam locomotive. A flash boiler can't blow up, can it? I can't find the failure mode for a flash boiler. Wickipedia's description is pretty vauge. Certainly, catastrophic failure could happen, but its not a crown sheet / pressure vessel type.

Here's a description of one from an Australian web site:

"Not strictly speaking a boiler at all, the concept of flash steam has been around since the 1800's and is common in instant on demand hot water systems today. The idea is to heat a long single pipe with a fire and pass only enough water through the pipe to create the amount of steam required at that moment by the engine. As only a small amount of water is heated at a time, this arrangement is efficient and effective. However it takes a skilled operator and is really only suited to smaller engines. This form of steam has been used effectively on such bizarre creatures as steam motorcylces. James Hansen added Flash boilers were also used very successfully in Stanley and White steam cars, to name only two. I have heard anecdotally that Henry Ford was originally torn between using steam or gasoline in his model T. Gas engines were new, and not well refined, while steam was essentially at it's peak, and worked extremely well and efficiently. The disadvantage was the time required to steam up- 5 minutes, but still, the gas engine was relatively instant. I say relatively, because I own a T. There is nothing instant about a model T... Flash boilers have the advantage that they need little attention, and produce very dry steam, as the hottest part of the tubing effectively acts as a superheater. The Stanley brothers held the land speed record for some time with their modified steam car. The boilers were hydro tested in public demonstrations to 1000psi. Nothing unsafe about them. [:)] Still used in steam jennies (cleaners) to my knowledge, just a copper coil with fire surrounding- poof you have steam. that's why they're called "flash" boilers, as the water tubes are at a heat sufficient to raise the feedwater to steam long before the water reaches the end of it's travel through the coil."

So....the question is, will the fittings hold? I don't know. My live steam engine is all brass construction, but operates at 40 psi. The brass is the same as it was when new, far as I can tell. Same on the electrically heated steam engine Mallard I regularly run in the basement. But that doesn't mean it will work on a full size locomotive.

Certainly, I hope these guys are successful. Since they are doing it for fun, and not for profit, I also hope that they don't cut corners. I also don't plan to be the first to ride behind it...

Mark
 

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What are the consequences of catastrophic failure then? It's not like they will be stranded halfway to the moon if the powerplant fails in this case. Will anyone be injured? Is it a possibility?

Chas
 

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Discussion Starter · #9 ·
Posted By wchasr on 04/30/2008 11:23 AM
What are the consequences of catastrophic failure then? It's not like they will be stranded halfway to the moon if the powerplant fails in this case. Will anyone be injured? Is it a possibility?

Chas





Catastropic boiler failure?... a big poof with a loud hiss and a cloud of steam. Unless you're close enough to get scalded there's not much to show.

Catastrophic running gear failure? Maybe some flying parts to worry about.

Either way some bumps and bruises when the train comes to an abrupt halt. And the passengers can probably walk back.

If it wasn't for the insurance companies possible reaction INDUSTRY WIDE to having to pay ANYTHING out, especially since it is an unproven unorthodox design... They pretty much view the rail preservation hobby people as "eccentrics" and charge accordingly...should they come to be viewed as "dangerous nuts", then there will be a lot of tourist roads and museums shutting their doors because they can't afford the premiums.

The fact that the group is "known' to be less than professional, the lack of published drawings, the design itself, and the lack of response to questions are all making everybody on the outside (and several people on the inside) kind of (rightfully) nervous
 

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Mik,

Looking at the pictures, it appears the cylinder rod passes through the front wall of the cylinder. This would add a second bearing location that in conjuntion with the rear wall would keep the cylinder from bending, and eliminating the need for a crosshead. This practice was used on alot of very small locomotives with small drivers, but failed misserably on larger locomotives where the stroke had to be longer to turn the larger drivers.

Personally looking at the photos I don't think this thing will last long. For one if you were making all new rods, I would have used tapered roller bearings at the ends, instead of bushings. Steam locomotive designers found this out and used them with great success during the end of steam construction.

Also your siderods are flat, which is fine if you plan on moving the locomotive only. If you were to take a cross section of the siderods of a full size locomtive, they would be an I-Beam formation, which is done for a reason. When the cylinder pushes on the siderod, and the siderod pushes on the wheels, the movement is going to occur at the point of least resistance. If you are pulling alot of weight, you have to move all the wheels, not just the locomotives, this increases the wheels resistance to move. With the flat siderods, as you attempt to pull a load, the siderods will want to deflect to the side because there is less material in that direction to resist the bending.

As far as building the frame out of box tubing this was a great idea. A box tube is by far very strong.

I have worked on 7-1/2" gauge live steam engines. And let me tell you there is NO WAY i would get close to that thing unless it had been inspected and approved. Too many people think just becuse they are small, there won't be any problems and they are WRONG!!! Small boilers are just as dangerous as large ones, the ONLY difference is the amount of damage they will do if they blow.

Just my thoughts.
 

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Interesting points. I am very interested to see how this little beasty works out in operation. If its successful I would love to see if this way of building can cross over to the backyard RR hobbiest, wouldnt you want your own narrow gauge RR? /DesktopModules/NTForums/themes/mls/emoticons/tongue.gif
 
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