> NBIC = National Board Inspection Code
> (document)
> NBBPVI = National Board of Boiler &
> Pressure Vessel Inspectors (organization)

NBBPVI writes the NBIC. Most (not all) states and many foreign countries have adopted the NBIC as their state codes. THE NBIC is and ANSI standard.

Most traction engine boilers are of butt-strap or lap-seam design. Over the years, it has become obvious that these designs, whether in traction engines or locomotives, are more prone to failure, as the seams are weaker than other designs. On the locomotive side, the NBIC and FRA address this issue by requiring more frequent and stringent inpsections of the seams. I see no reason why traction engines hould not be treated the same way.

Iowa is another state where engine operators managed to get a very lenient boiler inspection law passed to cover traction engines.

I think anyone who has been in and around the steam tractor side of this hobby can identify with all that is being said about safe and unsafe operation of steam tractors. The key is proper maintainence, annual inspections, and a set of reasonable standards to work by for safe operation. You hear all kind of horror stories about shell thickness, etc. but you dont hear about the fusiable plugs that havent been inspected since they were installed, or the build up of scale and debris at the opening to the boiler on the water glass valve at the bottom, thus giving you a false reading on water level,or the improper methods used to store a tractor after it has been fired, and also improperly inspected pop off valves. The comment about the steam tractor group educating its people is true there are several good schools for people to go to and learn the right way to do things. I worked for a shop that built 1/2 & 1/4 scale tractors and did major repairs to full size tractors. We even had a boiler built to replace a worn out one on a Frick. This boiler and the scale boilers were all built to ASME code. During my time there as we traveled to several shows in the state and did inspections under the antique code of the State law we saw some real junk. Was doing a hydro on a Case at a show and put my pen knife through the front flue sheet at the bottom of the smoke box. The owner went nuts and accused me of ruining his boiler. On further inspection we found over 2" of scale buildup in the mud ring and staybolts that were 1/3 of their original size. We also had a scale locomotive come in to the shop for work and when we removed the old flues we found they were schedual 80 pipe not flue material. To this day I will not go near anything that indivdual owns when it is under steam. The Ohio accident has made a lot of people think about the overall safety of these boilers but what about the failure several years ago in Penn. where the crew received severe burns from a boiler failure. Boiler failure is preventable by proper maintaince and good inspecitons. Education of owners and operators is the key to prevention of accidents.

johndeck@cox.net

> I think anyone who has been in and around
> the steam tractor side of this hobby can
> identify with all that is being said about
> safe and unsafe operation of steam tractors.

> The key is proper maintainence, annual
> inspections, and a set of reasonable
> standards to work by for safe operation.

> The Ohio accident
> has made a lot of people think about the
> overall safety of these boilers but what
> about the failure several years ago in Penn.
> where the crew received severe burns from a
> boiler failure. Boiler failure is
> preventable by proper maintaince and good
> inspecitons. Education of owners and
> operators is the key to prevention of
> accidents.

Absolutely, John. It's human nature that people dislike change, and resist being told what they can or can't do with their machines. The same attitude exists in some pockets of the steam railroad industry.

One of the first reactions to any new regulatory proposal is denial...."I've never heard of anything like ________ happening, so this is unnecessary." But in all cases, it HAS happened; the individual hadn't heard about it (or didn't want to hear about it). In the past couple of decades there have been several major traction engine boiler failures.

The current issue of STEAM TRACTION Magazine has an excellent article entitled "Boiler Shopping 101," which has some excellent information and guidelines on how to get a new traction engine boiler built, and how to weed out the phoney shops and bad designs so that a purchaser gets a solid, compliant boiler and not a shiny new boat anchor.

Still, the NBIC and/or FRA codes should be seen by prudent operators as minimal standards; part of the entry price of playing the steam game.

IMO, if an individual or group, be they traction or railroad, is unwilling or unable to meet minimal standards, they have no right to be operating these things where they can endanger the public. Fire up the questionable old Case in your pasture if you want, but keep the public well out of harms way.

> Iowa is another state where engine operators
> managed to get a very lenient boiler
> inspection law passed to cover traction
> engines.

Seriously, in your opinion, does this mean one should beware of attending a steam tractor meet in the state of Iowa?

> NBBPVI writes the NBIC. Most (not all)
> states and many foreign countries have
> adopted the NBIC as their state codes. THE
> NBIC is and ANSI standard.

> Most traction engine boilers are of
> butt-strap or lap-seam design. Over the
> years, it has become obvious that these
> designs, whether in traction engines or
> locomotives, are more prone to failure, as
> the seams are weaker than other designs.

When and where did this become obvious? A lap seam boiler is just a little less efficient than a butt strapp (when compared to the stregth of the parent metal). Please explain to me just what other type of seam constructions there are available in a rivited boiler other than a lap or butt strap seam? i will also observe that there is a purpetuated myth of the longitudonal seam letting go; if the seam, whether lap or strap is properly designed constructed, and maintained that just doesn't, and didn't happen.

Even in the Medina incident, the riveted seams held.

we must not fall victom to this lunitic idea that rivited boiler construction is obsolete or unsafe in any way.

It is, however, more expensive than welding.

In the past couple
> of decades there have been several major
> traction engine boiler failures.

Other than Medina, the only other major traction engine incident I can think of occured about 1969. Both were of engines that had not been inspected by an official body and both were low water crownsheet failures.

Several indicates more than two, and I would be curious as to when and where these other incidents occured.

> In the past couple

> Other than Medina, the only other major
> traction engine incident I can think of
> occured about 1969. Both were of engines
> that had not been inspected by an official
> body and both were low water crownsheet
> failures.

> Several indicates more than two, and I would
> be curious as to when and where these other
> incidents occured.

Ummmm. Was Medina simply a low water event? The report summary that I read indicated that it was a structural failure/over pressure rather than a burned sheet.

One thing to consider with the traction engines is that they were built with weight in mind and they were constructed with as thin as sheets as possible to keep the weights as low as possible so they wouldb't be too heavy to move. so if you calculate the working presure with an adiquate margin of safety there is no allowence for errosion. and boiler steel does errode without proper water treatment.

I have seen samples of a traction crownsheet where there is over 50% reduction of the sheet and the crown bolts.

The bottom line is if we all want to continue playing with our toys we need to do so responcibily. That meens if you arn't sure if it's safe, find out. and if it isn't safe, don't run it or fix it properly.


pfdx@aol.com

> Ummmm. Was Medina simply a low water event?
> The report summary that I read indicated
> that it was a structural failure/over
> pressure rather than a burned sheet.

> One thing to consider with the traction
> engines is that they were built with weight
> in mind and they were constructed with as
> thin as sheets as possible to keep the
> weights as low as possible so they wouldb't
> be too heavy to move. so if you calculate
> the working presure with an adiquate margin
> of safety there is no allowence for
> errosion. and boiler steel does errode
> without proper water treatment.

> I have seen samples of a traction crownsheet
> where there is over 50% reduction of the
> sheet and the crown bolts.

> The bottom line is if we all want to
> continue playing with our toys we need to do
> so responcibily. That meens if you arn't
> sure if it's safe, find out. and if it isn't
> safe, don't run it or fix it properly.

The state of Ohio determined that it was a low water event, although the crown sheet wasting was a contributing factor. John Peyton of PA, who is no friend of any rivited boiler, put out some propaganda otherwise, citing amongst other things the fact that the fusable plug didn't melt out. Upon testing, the plug did not melt out at over 1000 degrees F. Old fusable plug turn to an unmeltable oxide after comparitively short period.

There were three reports, and two of them indicated it was operator effor/low water (just like Gettysburg).

I would also submit that all boilers were designed to make the best use of materials: no one, not locomotive, power plnt,ship,or traction engine designers used more material thaneeded to insure a factor of safety. I can think of NO instance where thinner sheets or narrower/fewer staybolts were used to save weight.

> Seriously, in your opinion, does this mean
> one should beware of attending a steam
> tractor meet in the state of Iowa?

I don't know how Iowa law reads, but several years ago some friends and I were treated to a tour of the Midwest Central shops and the former Shop Services establishment by the late Stan Matthews, during their annual show. Stan described the insurance and inspection regime that the Mount Pleasant show had instituted. As a footnote, he also described some astonishing things that had been found and rejected by the show inspectors (but which may - or may not- have been legal under state law).

So I expect you can see the fabulous show at Mount Pleasant in confidence. My favorite, after the beautiful 2-6-0 and the smooth-running Shay was the gas tractor that was controlled by reins by a farmer walking behind it, like a plow horse.

- Aarne Frobom

> I would also submit that all boilers were
> designed to make the best use of materials:
> no one, not locomotive, power plnt,ship,or
> traction engine designers used more material
> thaneeded to insure a factor of safety.

On the contrary, I have more than once been thankful that, particularly on logging and industrial power,a large amount of margin was inherent in the thickness of the plate used. Baldwin loggers particularly impress me with extra stout barrels on those I have worked on.

dave

irondave@bellsouth.net

I think part of it is that calculations for barrels in well designed riveted seam locomotive boilers generally prove weakest along the outer row of rivets in a butt strapped longitudinal seam. Lap seams have some mechanical reactions to stress which may tend to fatigue the edges of the seam or promote undercutting between the lapped parts which are not apparent to visual inspection.

Two kinds of error cause almost all failures: Incompetent inspection / maintainence / repair or incompetent operation. The fact that some pretty marginal boilers have operated without failing shows just how forgiving they can be of some amount of both of the above. But, margin diminishes until it reaches its weakest critical mass and then results can be anything from annoying to catastrophic.

I can't understand how anybody owning or operating a steam boiler is willing to stand next to it under pressure without knowing by personal inspection and calculation that it is in fact provably safe. "It hasn't blown up yet" isn't adequate proof in my opinion.

dave

irondave@bellsouth.net

> So I expect you can see the fabulous show at
> Mount Pleasant in confidence. My favorite,
> after the beautiful 2-6-0 and the
> smooth-running Shay was the gas tractor that
> was controlled by reins by a farmer walking
> behind it, like a plow horse.

> - Aarne Frobom

Ah, you read my mind. I know they always have a large number of boilers steamed up and I've never seen or heard of a problem.

And I remember the tractor being hooked to a buggy so he could ride behind it while handling the reins! My favorites are usually the saw mills, grinders, etc. driven by hundred-foot long flapping belts.

I have some experience with with railroad locomotive boilers, a little bit of experience with traction boilers, and am on the board of directors of a live steam society which had extensive discussions with our State regulatory agency about model boilers versus "historic" boilers about a year ago.

In my state, model boilers have their own regulatory section separate from the historic boilers. Many years ago, competent P.E's who were leaders in the club helped to draft a regulation that the State Department of Labor and Licensing was comfortable with. These P.E.'s were competent enough that the governor appointed one of them to a term on the State Boiler Board.

Model boilers in my state are built and inspected to a standard such that while they are not ASME (it is impossible to build boilers under about 12" dia to strict ASME, as you cannot hang the smallest available ASME safety valve on it!)there is a high degree of confidence in the safety in conjunction with proper operation. While Jim defends his particular state's regulation of traction engines, my experience is that there is a minority of tractor operators in my state that are constantly chafing and trying to skirt parts of our historic boiler regs, including such activity as "I don't need a second safety valve, my tractor has never run with two safety valves", and some such. In our experience as model operators, they put our inspectors in a bad mood about amateur operators, and having to defend ourselves and keep an eye on what they do with the boiler board uses up energy better spent elsewhere.

Frankly, in most states "farm" boilers were exempt from state Labor and Licensing regulations, and as such, the maintenance was totally up to the education and dilligence of the owner/operator. Also, a high percentage of tractor boilers are lap seamed. By its very nature a lap seam has to bend back and forth with the expansion and contraction of the boiler with heat up/cool down, and will be more suceptible to seam cracking. There are known tracor operators that insist on operating their lap seamed boilers at over 100 psi, which is the national standard for this condition. Also in most tractors the boiler IS the frame and draft structure of the machine, putting more stresses on the boiler structure, particularly in the firebox plates.

I do believe that the poor tractor operators are in the minority, however, I am concerned that if more cases like Medina happen, the good work done by years of ICC/FRA oversite, and the recent fine work of the Working Group on Locomotive Boilers could go for naught if a riveted firebox boiler is launched and public outcry and/or loss of the ability to purchase insurance policies results in making it more difficult to operate our boilers.

Steve

SZuiderveen@aol.com

> When and where did this become obvious? A
> lap seam boiler is just a little less
> efficient than a butt strapp (when compared
> to the stregth of the parent metal). Please
> explain to me just what other type of seam
> constructions there are available in a
> rivited boiler other than a lap or butt
> strap seam? i will also observe that there
> is a purpetuated myth of the longitudonal
> seam letting go; if the seam, whether lap or
> strap is properly designed constructed, and
> maintained that just doesn't, and didn't
> happen.

> Even in the Medina incident, the riveted
> seams held.

> we must not fall victom to this lunitic idea
> that rivited boiler construction is obsolete
> or unsafe in any way.

> It is, however, more expensive than welding.

Riveted boiler construction is obsolete, and has been for many decades. That does NOT mean existing riveted boilers must be outlawed, but that they must be maintained properly and the known weaker ones (particularly lap-seam boilers, none of which were built after the 1930's due to the problems of weakness along the seam due to mechanical stresses) must be inspected even more closely and more often.

Note that welded boilers were just being introduced in the locomotive industry when the diesel showed what it could do and suddenly nobody cared any more.

When most of these things were built, welding was an exotic technology, while riveting had been around for generations and everyone had a comfort level with it. Now the tables are turned; welding is not only accepted but is superior, and proper riveting is close to becoming a lot art, as is the manufacture of pressure vessel rivets. We're not talking about structurla rivets here (such as for bridges or buildings), but pressure vessel rivets.

And it isn't a myth, Reverend. The area along the lap seam is subjected to the highest stresses due to the flexing of fire-up, cool down, and pressure fluctuations while fired up. Left to go on long enough, this turns the seam into a potential zipper.

Better methods include the use of doublers over (and sometimes under) the seams, as was done in locomotive boilers. That completely stops the bending stresses that are inherent in the lap seam design.

If lap seams were so safe, you could still buy new boilers with lap seams.

Steam REalist

I have worked on and around all kinds of boilers for well over half my life, and have made a big part of my life's study boilers, boiler safety, and design. I have a boiler operators liscence from a Code state, and have worked closely with several states and the FRA. From whence do you devine your pronouncements?

Even the ASME and National Boards admit that rivited construction and repair of pressure vessels has been supplanted largely due to economics, not any inherent safety issues.

Want to know a little secret? A lot of longitudonal seams were gas welded and had welt plates (straps)applied over them because the rivited, butt strap seam was needed to insure strength (at least Baldwin did).

And I still suspect that a totally welded boiler has a lot more opportunity to introduce stress into the vessel, which is why annealing is so important.

I just do not appreciate an inaccurate portrayal of rivited seams as inadequate or inherently unsafe. Without digging out my tables, a double rivited lap seam is about 60% effecient, and a well designed butt strap works out to around 87%. A well designed rivited boiler is nothing to be scared of if it is good shape.

Yes, welding is one reason that a typical power boiler will have 1/4" shell thickness(compared to the old days much smaller factor of safety) while in the old days a 7/16"sheet was a minimal norm. But my local boiler shop calls the new boilers "throw aways". But I still maintain that welding as a method supplanted riviting largely as an economic factor,not a safety one.