Dear Nathan:
The two SY class steam locomotives in the U.S. (SY1647M and SY1658M) were built to be "equivalent" to then current ASME standards. Our modifications to the standard SY design included the use of full penetration welding at all pressure retaining points in the boiler and firebox including staybolts.
The 1800 (+/-) standard SYs in China use fillet welded staybolts, etc. as do the one JS class and three QJ class locomotives brought here.
J.David

Mr. Peartree:

I am surprised with all your careful reading of old posts you missed my Tue Jan 05, 2010 3:38 pm post in which the referenced material describes in detail why staybolts break. As Dr. Greenslade (Flannery) fully supported the work of Dr. Tross (German Federal Railways,) I see no better theory to support. The development of the profiled staybolt and fillet-weld attachment occurred at a time in Germany when extensive resources were put into steam locomotive development. The work was presented by Dr. Greenslade in the 50's, but by that time we were folding up the tents.

"What I do not understand is necessarily wrong." - Brazilian Office Theory - L.D. Porta

I don't have anything further to add to this discussion.

To mjanssen;
Upon reading the Henschel book on steam locomotive design features that they offered, Henschel states that cylindrical staybolts, when fillet welded, are prone to failure. That is why they recommended the Tross Staybolt. So the question is...Do we propose submitting to the main committee of A.S.M.E. that Tross bolts be included in the 2013 edition of Section I, or are we proposing the stuffing of a piece of A-36 round bar in a hole and fillet welding each end, while ignoring the requirements for certifying the welding process qualifications and the welder qualifications as directed by Section IX of the Code?

To All:

I posted earlier about my experience finding crevice corrosion cracks in low pressure boiler fillet welded stays. Aside from this, I don't have a "dog in this fight" concerning threaded, full pen welded, or fillet welded stays. I'll yield to folks that have more to bring to the table for discussion.

However, I DO want to remind everyone, including the ESC, that this staybolt welding issue is much larger than locomotive boilers. The methodology used in locomotive boilers will most likely have to parallel the rest of the code; in other words, if a fillet weld is good enough for a locomotive boiler, it must be good for a stationary boiler.

I highly doubt that the ASME will adopt a rule that in power boilers stay welds must be a full pen weld (current rule) but may be a fillet if on a locomotive boiler.

More to chew on......

That's like saying an artificial hip must also be used as an elbow. Locomotive boilers are not stationary boilers, and those built or rebuilt as if they are have not done well. Forcing inappropriate techniques because they are already codified for other purposes defeats the purpose of having a rational and proven safe and effective set of standards and practices to work from.

dave

Mr. Janssen;
You have stated correctly that A.S.M.E. Section VIII does allow fillet welded staybolts, however there are a few things overlooked in that statement. In Section VIII UW-19.3b, a fillet welded bolt is shown, however it must have a minimum throat thickness of "t", which is the thickness of the plate being stayed. In Section I PW-19.3, it states that the staybolt shall not project more than 3/8" beyond surfaces exposed to products of combustion, and Section I PG-46.2 states that the minimum plate thickness of a stayed sheet is 5/16". To do this weld per Section VIII, the projection of the staybolt would be at least 0.442", which is not allowed by Section I. As the firebox sheets get thicker, it gets worse, with the projection of the staybolt being 0.707" minimum for a 1/2" thick firebox. The key point to remember is that Section VIII applies to unfired pressure vessels, and Section I applies to power boilers.

Dear Mr. Jannsen,

It is always interesting to see ones references (or apparent single reference in this case?) to an idea. The English edition of the book La Locomotive a Vapeur discusses both the Czech and the American approaches to the welded boiler and they are different. Not the least of which was the heat treating of entire boiler which was the American practice. But the problem with studying historic technology is the fact technology does change with time. As stated in the book, The Procedure Handbook of Arc Welding published by the James F. Lincoln Arc Welding Foundation “The art of welded steel design has been evolving gradually, with all the errors that normally accompany an evolutionary process.” To that end the first edition was printed in Sept 1933 and they have had several additions since including May of 2000. Given that scope of time I assume they have seen a few changes to both welding theory and practice.

The issues here are not of a simple nature. Consider that the American Welding Society (AWS) has established that the allowable shear value for weld metal in a fillet or partial-penetration bevel grove weld at;

T= 0.30(electrode min Specified Tensile Strength)

And they have proved this equations validity with a series of Fillet weld test with a series of fillet weld test conducted by a special task committee of the American Institute of Steel Construction (AISC) and AWS. For the record the welds described in The Procedure Handbook of Arc Welding are a T intersection similar to the installation SP used on 2-8-0 3420’s front tube sheet and a stress riser situation.

Before I move on I want to define the term Allowable. “Allowable” weld strengths are specified by the AWS and AISC and various other engineering and governmental organizations to make sure that the weld can deliver the mechanical properties of the plate being joined. Allowables are designated for various types of welds under steady and fatigue loads.

Consider the following paragraph from The Procedure Handbook of Arc Welding pg 2.3-2, “The existence of tension forces transverse to the axis of the weld or shear in any direction, Figs 2-122e and 2-122f (T intersection fillet welds and stress riser fillet welded plate) requires the use of weld metal allowables that are the same as those used for filet welds. The selected material may have mechanical properties higher or lower than those of the material being joined. If the weld has a lower strength, however, its allowable must be used for calculating weld size or maximum allowable weld stress. For higher strength weld metal, the weld allowable may not exceed the allowable of the matching weld metal for the metal being joined. The allowable used shall not exceed the shear allowable of the plate.”

The next question in my mind that needs to be answered is what type of loading does a locomotive boiler experience and in what environment. A locomotive boiler undergoes a lot of cyclic loading particularly in this weekend only type of operation that many locomotives see today. A 200 psi boiler can go from ambient temperature to 390F and a 300 psi boiler will reach over 417F according to the Marks and Davis tables. Given that in some engine houses that ambient temperature can be well below freezing it shows just how much a temperature swing boiler has to endure just at start up. Then add fluxuation of both temperature and pressure due to crew inexperience (and/or inadequate/misguided training) and other issues and a boiler can undergo a lot of stress and strain. Water treatment is another area of little understanding that has a great influence on boiler life.

The Procedure Handbook of Arc Welding speaks about allowable Fatigue strengths of welds. “The performance of a weld under cycles of stress is an important consideration in structures and machinery and the specifications relating thereto have been developed after extensive research by the AISC. In the case of a complete-penetration groove weld, the reinforcement and any undercut, lack of penetration or crack will act as a notch, which interns act as a stress raiser and results in a lower fatigue strength. The very nature of a fillet weld, because it is used in lap and tee joints provide an abrupt change in section that lowers fatigue strength.” I specifically included the potential limitations of full penetration welds because we understand how to overcome these deficiencies which by design can not be overcome with a fillet weld. The AISC has fatigue specifications that cover a wide range of welded joints and the fatigue strength of members attached by welds.

Let us consider the issue of cracking. The major cause of cracking in the base metal or weld are high carbon resulting in increased potential for hardenability, high cooling rates, joint restraint, improper weld bead shape, hydrogen pickup and contaminates on the plate or electrode.. Everybody’s favorite Iron-Carbon phase diagram tells this story for the issue of both carbon content and rapid cooling rates.

The bottom line in any tourist RR is cost. Fillet welds are easy to apply and require little or no plate preparation. They can be made using large diameter electrode with high welding currents and as a consequence the deposition rate is high. The cost of the weld increases as the square of the leg size. A double bevel grove weld has about ½ the weld area of a fillet weld. It does require extra preparation but it does use smaller electrodes with lower welding current to place the initial pass without melting through. While this first pass has a high initial cost of time per amount of metal laid as the size of the plate thickness increases the initial weld becomes a less important factor in the total cost and you find that eventually that full penetration welds are actually cheaper than fillets.

Now let me raise a concern of approach, in two of your post you have the following quotes quote “"What I do not understand is necessarily wrong." - Brazilian Office Theory - L.D. Porta.” and “"Know that what is not written down doesn't exist." - Livio Dante Porta”. A lack of knowledge has never been a defense in court. Many engineering mistakes have lead to significant loss of life due to a lack of knowledge that was developed only after a tragedy. Just because things were not known did not prevent tragic events from occurring. I strongly encourage you and anyone else to continually learn new things. To that end, the University of Idaho has a Materials Science Engineering program which may enlighten you.


Robby Peartree

Robby and Nathan,

Thanks for all the input. I am glad to see such an interest in new locomotive boiler design is shared. I hope you presented your comments to the ASME request as you both have good insights. As I said before, I have no further comments on the issue.

I think that there will be an English copy of the German TRD code available to the ASME locomotive task group, as it appears to be what has been used in the most recent larger boiler construction in the World (England, Germany, and now Australia (I believe.)) That does not necessary mean it is a recipe for building boilers here, but may none the less provide some level of enlightenment as to alternatives to our traditional way of doing things.

What the consensus decides to do with the information is to be seen, but I hope that it advances steam as much effort was made in fostering the idea.

BTW Robby, you are exactly right about the quotes.

Regards,

Matt

Matt,

I have been unable to download the FWS files at wrrc. The website reports file not found. I've also tried Arizona Mechanical Engineering. The files there download but only the first page of each is readable. As this thread seems preoccupied with Tross staybolts it would be nice to have files available.

I have found Tross's US and Great Britain patents and they do help explain some of what is going on -- the British one better than the US--,but I would really like to see what experiments were run and any mathematical modeling and derivations.

Beyond the Tross staybolts, I wonder if the current section I incorporates a requirement to replace the cross-section of crownsheet removed in the installation of a thermic syphon. This manifests as gussets across the syphon opening in the crownsheet. The 1947 and 1952 section III's do have something about this. I don't know if any earlier codes had this. I don't think the one in force in 1941 did as 1225 was built without such despite a specification that the boiler be built to ASME code except for paperwork. 1925, 1930, 1938, and 1941 Locomotive Cyclopedias don't show gussets in thermic syphon drawings while 1947 does. Given, the pre-1952 repair welds in the crownsheet in front of the syphons on 1225 that probably resulted from the unsupported syphon opening, I think the provision in the '52 code has merit and should be part of any new code.

Just out of curiosity does 765 have these gussets? How about 2789?

Keep up the good work on the ESC. And thanks in advance for any help on finding or fixing the Tross staybolt files.


Andrew Adams

I'd sure like to know a LOT more about Tross stays and fillet welded stays - and whether fillet welded stays made to the Tross pattern might be as strong and robust as full penetration welded rigid "stock" stays. Please correct any wrench turners, not mathematicians, misperceptions, but it seems Tross' genius was in creating a design that obviated to some extent the inflexibility of plain stays and moved the stress point we all know too well away from the junction of the stay and wrapper sheet, spreading out through the length of the stay instead. If stresses can be so distributed might it be possible a safe and useful fillet welding practice might be found that can be included in our standards? Does this body of information exist or do we need to do some testing?

Again, trying to interpret from little information but intriguing stuff........and welcoming any corrections.

dave

Andrew,

I got the error, too, and mentioned it to WRC. You can PM me and I'll email them to you if they don't post a fix.

Yes, they do seem preoccupied with the fillet weld rather than all of Dr. Tross's work.

I have also the resulting latest railroad practice from Tross's work (DV 946, 1959) that I had translated by DB Meinigen's English-speaking rep.

I don't have any data on the locomotives you mention, but that is very interesting.

Dave, the design that I worked on with Dave Griner for a Tross staybolt while at Wasatch basically took the standard shaft size of a particular boiler as the minimum diameter for the staybolt and then the shaft diameter enlarged at the sheets to something around the largest oversize, following Tross's basic proportions for the BTH staybolt. I made an Excel spreadsheet that generates a profile for any length and minimum/maximum shaft sizes the user inputs for WRC. It is a compromise of American/Tross design, but is certainly an improvement in distributing the stress across the shaft that does not cross any regulatory barriers if used with an approved attachment. Interestingly enough, others I have spoken with in the U.S. who have studied the Tross papers came up with almost the exact same thing. As using the Tross profile this way basically creates enlarged heads (and therefore enlarged attachments) it improves the problems Nathan and Robby discuss in their posts regrading the fillet weld attachment. It should be noted, however, that the fillet welded staybolt stress calculations on the Chinese locomotives here (which have straight -shaft 18mm bolts I believe) have been made and submitted to the FRA as part of their Form 4.

The Tross BTH staybolt with the same minimum diameter as a plain shaft stay can bend further and remain within its elastic limits at all points across the shaft. It is interesting to note that German flexible bolts are not typically ball and socket, but have a flat seat with spring washer to the wrapper with a hole of considerable clearance. The washer is just snug when cold. I'll probably ship my cross-sectioned sample of DB 01-1100's old firebox to Strasburg so everyone who wants to can look at it.

Mr. Janssen

With due respect, my time spent on the subject of fillet welding on boilers is not a preoccupation but an attempt to educate people on the potential dangers of such move. And that position is not just my own but the view of several highly educated and respected professional engineers.

Respectfully
Robby Peartree

Matt, Andrew, etc.

Thank you for the heads up about the file download errors. There appeared to be some bad file names in our archive, and I believe I have resolved the problem.

You should be able to obtain the files now by visiting the "PDF Documents > Technical Documents" category at http://files.wrrc.us/. My apologies for the inconvenience. If there are still any further issues, please do not hesitate to send me a private message.

Thank you,

Well Robby, I guess I do have a little more to add to the thread from a more general perspective and perhaps get it more centralized on the Topic.

As fillet welded staybolts seem to be by far the majority method of attachment used in locomotive boilers in the World both in the recent past (post 1950 Germany, Russia, Poland, China) and currently on larger boilers in Germany (01-1100), The UK (A1 Tornado), and now Australia (3801) and almost all other locomotive boilers coming out of Meinigen, ZOS Ceské Velenice, InterLok, as well as a standard application for repairs in Switzerland, one might want to review carefully if, in fact, all the engineers in the World are wrong or if a few American engineers are right.

The majority of the most recent experience in the World in terms of number of staybolt service hours (6500 locomotives/ .5 million+ bolts in Chinese Locomotives in regular service through 1990's, .5 million+ bolts more in regular service in Eastern Germany, Polland, Czech Republic through 1960's) is with the fillet-welded staybolt. It seems the full-pen weld is actually most questionable, as it has the least total locomotive service hours.

A threaded bolt attachment with fillet weld (A.K.A. seal weld) seems to be the most conservative method as it is essentially a union of the two styles with the most service hours, providing 2x redundancy.

I have seen and saved a number of samples where the threaded attachment had failed and the staybolt had been "seal welded" because the staybolt was leaking. When one cross-sections the sheet and bolt (as we have had the opportunity to do) one finds that this is repair is often, in fact, an alteration to the fillet weld method of attachment. While I am by no means advocating this, it is simply interesting to note that a lot of the typical locomotive boilers in service in the U.S. where the bolts were seal-welded in the late steam era or by later operators, are probably held together by fillet welded staybolts.

I'm not going to tear apart anyone's reasoning for why the fillet weld won't work in the U.S. The justification is within the code and the methodology of its teaching as you and others point out. It would require a "paradigm shift" in thinking which would require a grate deal of education and perceived danger to the establishment. If the ASME desires, however, to be the predominantly used code in the World, they will likely have to adopt the fillet welded staybolt for stayed construction with similar leg size requirements to the German TRD code. Otherwise, the rest of the World will use TRD code under the Pressure Equipment Directive (PED.) Importing CE stamp locomotive boilers from one of the current approved CE approved manufacturers may also occur in the U.S. as is currently occurring in other countries as the precedent for this type of construction is already established for FRA jurisdiction.

Finally, to get back to the intent of the thread, I think stayed locomotive boiler construction has a small place in the future of locomotive boilers - primarily in the area of preservation - compared to the water tube firebox or watertube boiler which offers an expanded thermodynamic cycle, which is necessary to achieve contemporary efficiencies and power densities. Given the likely number of staybolt installations and service hours in the future and total costs of operating Generation 0 and 1 steam, the attachment method chosen has little economic impact on repair costs. It would lead one to choose the highest quality design possible though, which to date is the Tross BTH staybolt body.

The story of steam locomotive itself is the very embodiment of a progressive gain in understanding of a rather simple concept with complicated mechanical and thermodynamic attributes. Hopefully we can all work together to preserve not only the steam locomotive, but preserve innovation of it - which has almost been lost.

Matt

This has been a very interesting discussion to say the least!

The last post mentions a form of attachment that includes threading and fillet welding, a practice that I have seen used and one that is used, and has been used, on some tourist lines in the US.

I submitted a paper to the ESC in the name of Wasatch Railroad Contractors. As I intend to participate in these meetings, my suggestion is actually that of incorporating a method like-unto that used in Switzerland (also found in the German Code mentioned by Mr. Janssen) That form of attachment actually allows a partial v'ing of the hole, but does not require the hole to be v'ed the entire depth of the hole. This is a mix/hybrid fillet welded bolt/Partial pen bolt attachment.

Dave L. Actually....it was made very clear....more than once. NO FOREIGN CODES WILL BE CONSIDERED IN THE FORMATION OF THIS NEW EDITION. PERIOD! If and only if this fillet welded bolt thing stands a chance, it will NOT stand a chance being copied from any other code....Australian, German, Swiss, Polish, Russian....need I go on? If we are to do this, we do it on our own. i.e.....we test, prove and debate on our own the merits of this form of attachment.

Wasatch, along with the Strasburg has tested (and Wasatch will again test) this form of attachment. These 100% US tests and test results will become the foundation upon which Wasatch enters this debate. Further, of the US based contracting companies (with what Kelly Anderson underlined as having EXPERIENCE) it is noted that Wasatch is the only (as far as we know) US based contractor with actual hands on EXPERIENCE with actual installation, inspection and continued oversight over fillet welded bolts...both Tross style and conventional stay bolts.

Finally to the esteemed Mr. Peartree,

Good Sir, you have spent a great deal of your life working at tourist railroads (which currently no line employees you...correct me if I am wrong). All of the lines you have worked at were members of TRAIN. All of the said lines had issues of TRAINLINE in their crew rooms....I have been to these crew rooms and seen the magazines. Robby, though news to you, all.....may I say ALL of the ESC meetings have been posted in the TRAINLINE with dates and times. The failure here is your ability to actually pick up a magazine and R.....EEEEEE......AAAAAA......DDDDDDD it! The ESC has been very public. They are very open. They have tolerated my comments and interaction for many years to which I am grateful. Robby, you are welcome to come. If it means that much to you...go and comment. Write a paper, present your information. To conclude this section; I disagree with you 100% in respect to fillet welded bolts. Robby, you have asked collage professors about this; most collage professors are in school because they can not function in the field.....before any of you flame me....I said MOST....no offense to those of you who can function in both fields. Again I return to Mr. Anderson's comment....EXPERIENCE. Robby, bring your fact backed, experience based and time proven EXPERIENCE to the table.....I would enjoy debating you on the issue. In respect to Mr. Janssen; Robby, Matt has spent far more time studying, talking, traveling, experiencing, learning and proving this method than you have spent in your entire life sitting on the toilet (that equates to a lot of time). Robby, until you can enter the debate with Experience, I suggest that you come prepared to learn and grow! It is always fun learning new things.

The upcoming debates will be fun. They will be educational. I hereby raise my hand and proclaim that I am coming to the meetings prepared to learn. I again voice support to a comment made by Kelly to Mr. Austin.....(in effect) Every time I open the book I learn something new. Every time I attend ESC I learn something new. I go to ESC to learn, to grow and explore....these are key elements to progression. If we as readers of RYPN expect this industry to survive, it must either learn to adapt to the changing world around it or be consumed by the changing world around it. I elect to change the industry rather than be consumed by a world that simply took an opportunity to eliminate, by natural selection, a weaker breed.....a breed (or should I say....B."READ") of people who can't "read" or learn. Knowledge is power!

Respectfully submitted,

John E. Rimmasch
Wasatch Railroad Contractors