Lap Riveted Boiler Seam - BAD!

dinwitty · **Joined:** Wed Oct 22, 2008 8:18 pm **Posts:** 2226

jim templin wrote:

Ok, Kiddos, a little boiler 101...a circumferential lap seam is different than a longitudanal lap seam, and is figured much differently than a long seam. The discussion here, as it has always been, is on the long seam. None of the "cracking "models described apply to a circumferential seam.

Just so you know, every steam locomotive I have ever seen has circumferential lap seams.
The Smithville explosion was not due to the either the circumferential seam letting go, nor the longitudanal lap letting go...this engine was overpressured to the point that the crown sheet was pulled off the crown stays. The engine was a series of Baldwin built moguls constructed either side of 1890, so this old hog had been in service for at least 20 plus years. Since the engine was in switching service, it was likely pretty low on the totum pole as far as getting money spent...at this time locomotives of this same age and class were being sold off to both shortlines and scrappers...I doubt that the "thorough overhaul" mentioned was the complete remanufacturing that we would envision. What we don't know is if there were any patches, reenforcements, ect. applied to areas of the firebox to compensate for wasting. Rivited reenforcement plates were common practice when thinning was found...just rivit a patch over the affected area, drill a weep hole to let you know its leaking, and go to town. Sometime these weep holes didn't get drilled, and the patches became a time bomb. On a socio-historic level, there was much alcohol abuse on the railroads than anyone would care to admit, but booze was a huge contributor to many accidents at that time. The term "asleep at the switch" could very more often have been "piss drunk at the switch." Prohibition came not because there was a grand design at moral reform, but the general abuse of alcohol was rampant. Remember, there was no Prozac, ect., and everything a man did to make a living was physically exhausting and usually hurt. Sorry to go OT.

The Smithville accident was a direct contributor to the ICC requirement that when setting SRV's a certified or weight tested guage must be used.

I have made my living on boilers, of all kinds, and have made their study a major part of my life...I think anyone putting forth armchair expertise is ill advised.

BTW thanks for the good words, Brer. John

We still have failure on the riveted seams in that explosion. It is an extreme condition but shows the limitations.

Dave, hope you like pistachios. :)

jim templin · **Posted:** Tue Mar 30, 2010 11:34 pm

I am aware of Newton, both Sir Isaac and Wayne...and until I see something with my own eyes to convince me otherwise, there are others factors in play here other than the physics of regular wear and tear.

And just so you know, I have inspected several lap seam boilers graced with an ASME cloverleaf with an S in the middle, and such were being constructed for service under a hundred psi until the economic end to riviting. I stand by emperical evidence, and theory and practice are oftimes two different animals.

I will also flatly state that a well designed, executed, and maintained lap joint is not to be feared.

John Deck · **Posted:** Wed Mar 31, 2010 10:21 am

The issue is about Lap Seam Boilers and the possibility of cracks forming in the area of the lap. I think Jim has given a good presention on what went on with the Smithville incident and I know this has been covered in numerous other sites. The picutures and available information do not show any indication of a lap seam failure and I agree with Jim's comments on this. I would like to ask you Dinwitty to stop trying to move this thread in a direction away from the serious discussion about the why and what that goes on in a boiler. This is serious to all of us that own and/or operate boilers. Your comment "We still have failure on the riveted seams in that explosion. It is an extreme condition but shows the limitations." does nothing unless you are able to illuminate further and show us how it relates to the subject at hand.

John Deck

jockellis · **Joined:** Sat Mar 27, 2010 11:30 am **Posts:** 2

Hi, I'm new here, having gotten the link to the photo on a Georgia Association of Railroad Passengers' e-mail.
I've always wondered how these boilers kept the pressure in. Was it just the tightness of the rivets pressing against the two sheets of formed metal? How did they get it that tight? I know that in about 1900 the technology of metallurgy was in still in a primitive state.
Jock Ellis
Level II NDT inspector, MPI, FPI, EC

survivingworldsteam · **Posted:** Wed Mar 31, 2010 11:26 am

dinwitty wrote:

A steam tractor (steam traction engine as we call it) likely works a rougher turf than your average steam engine, running on dirt and rocks and clunking around.
So being under pressure and roughing it and any metal faults adds to the fatigue.

Glad to see the problem found and perhaps news a new boiler was in order.

In many instances (i.e. Case traction engines); the boiler is actually a load carrying member; with the rear wheels mounted to the firebox, the front wheels mounted on a pedestal on the front of the boiler, and the engine mounted on top. You have a whole lot more than just steam pressure tugging and twisting at those boiler seams.

jim templin · **Posted:** Wed Mar 31, 2010 11:38 am

jockellis wrote:

Hi, I'm new here, having gotten the link to the photo on a Georgia Association of Railroad Passengers' e-mail.
I've always wondered how these boilers kept the pressure in. Was it just the tightness of the rivets pressing against the two sheets of formed metal? How did they get it that tight? I know that in about 1900 the technology of metallurgy was in still in a primitive state.
Jock Ellis
Level II NDT inspector, MPI, FPI, EC

No, you don't know that. Metallurgy in 1900 was NOT in a primitive state, it was quite advanced, actually. In fact, except for developments made possible by the used of modern atomic study, and some modern alloying techniques, the manufacture of steel, especially for boilers, was in many ways superior to the modern product. There is a desire now for higher tensile strengths, and varying hardness, but the chemestry of making good material was highly developed in the early 20th century.

And, yes, a rivited boiler is held together solely by the holding power of the rivit, with caulking done on seams to seal them up. The caulking described is the pressing of parent metal into the seams by hammering with a special tool. The rivits were installed red hot, gunned in, and drew even tighter due to the cooling.

mikefrommontana · **Posted:** Wed Mar 31, 2010 1:05 pm

If the photo that started this is from a traction engine, then one thing that would cause the inward curve of the joint could be that the boiler was left bottled up under pressure (main shut off valve and injectors/water supply valves closed) so that the boiler was under implosion stresses as it cooled. Any cracking near a seam could exacerbate the collapse of the vessel. If this happened multiple times, it could be the cause of the crack.

I would suspect that railroad locomotive boilers tend to be harder to seal and so are not as prone to carrying vacuum loads when cooling. One sign of vacuum loading will be tendency of a boiler to fill itself completely through the injectors (if the water supply is not equipped with shut offs).

Mark Jordan · **Joined:** Fri Nov 07, 2008 11:21 am **Posts:** 490

Yes, there are external loads on a traction engine boiler. However, some like mine (Frick) have a frame and no load is placed on the boiler. Even with the external loads applied, there isn't any particular load that I'm aware of that is focused on the longitudinal seam. Most of the external load is focused on the firebox throat and wrapper sheets.

1) So far, I'm in general agreement with Jim Templin. Sir Templin and myself are keenly aware of the physics of lap joint, butt joint, and welded construction. We also have studied to a reasonable degree the metallurgy of the era, and boiler construction practices.

2) A friend what has been mentioned here has brought up a couple of interesting thoughts:

a) There is a coating that looks like silver paint on the inside of the joint, and that the inside surface doesn't look like the typical waterspace of a boiler. I have discussed Apexior (or similar) but there is still the overall question of if this is indeed even a chunk of boiler at all?

b) The outside caulking edge is not shown. As a matter of fact, the caulking edge is a considerable distance from the rivets.....so much that the question of the ability to even caulk this is possible?? Again, is this really a boiler part?

I have stated that this appears to be a lap seam crack, and it does according to photos I've seen, but it's location relative to the surrounding joint areas is suspect.

I guess we REALLY need some more info here???? The information needed are more photos from all sides of the chunk of metal in the first photo of this thread.

jim templin · **Posted:** Thu Apr 01, 2010 2:39 pm

Could this section be from the fire flue (morrison tube) of a scotch marine or ramsbottom boiler? That would explain the lack of waterside evidence.

Dave · **Posted:** Thu Apr 01, 2010 7:28 pm

I'm going to go out on a limb here and figure it is what it is purported to be - a section from the shell of a fire tube locomotive style boiler. I chalk up the light colored stuff on the water side as light scale, or a use of aluminum paint as a preservative that didn't. Debating the veracity of the sample is an interesting but less enlightening endeavor than considering the form of deterioration shown, and its implications.

dave

Rob Bryce · **Joined:** Wed Mar 31, 2010 11:50 pm **Posts:** 1

dinwitty wrote:

A steam tractor (steam traction engine as we call it) likely works a rougher turf than your average steam engine, running on dirt and rocks and clunking around.
So being under pressure and roughing it and any metal faults adds to the fatigue.

I would also question the statement that a traction engine sees rougher turf. Top governed speed is usually around 1.9-2.7mph. Dirt is soft and is often displaced during an engine's movement. Rails are quite hard in comparison, and a locomotive sees much higher speeds and thus shock loads. There seems to be record of railway loco's breaking staybolts, but we (around here) have no indication of a staybolt ever cracking on a traction engine.

Getting back to the longitudinal lap seam: as you look through old code books, there seems to be a far greater concern for the internal lap on an HRT, than on any external lap. Also, I've got quotes where there was a greater concern with loads imposed on the boiler due to expansion/contraction in large boilers of different type construction due to temperature, not due to pressure.

In the end, we can (and here do) conclusively test via NDT for cracks in a lap seam (on the dome or on the barrel). No flaws have been found on any lap we've tested to date.

Certainly a topic worthy of lengthy discussion!

--Rob

Mark Jordan · **Joined:** Fri Nov 07, 2008 11:21 am **Posts:** 490

Quote:

There seems to be record of railway loco's breaking staybolts, but we (around here) have no indication of a staybolt ever cracking on a traction engine.

TRUE!

However, the dynamic load from bouncing around has minimal impact on bolt failure. There are basically two considerations:

1) Traction engine boilers are smaller than locomotives, and thus the firebox expands/contracts less RELATIVELY to the outside sheets, thus bolt breakage is minimal, if any. Likewise, the dinky lokies had far fewer bolt problems than the big articulateds, again due to sheer size.

2) Traction engine production ended about 1925+, whereas locomotives were built into the 1950's. Traction engine boilers routinely used wrought iron for staybolts and braces, whereas locomotives normally used steel. The steel was stronger, allowing higher working pressures, but is more susceptible to cracking, and crevice corrosion (within thread troughs).

J.B.Bane · **Joined:** Wed Aug 25, 2004 9:53 pm **Posts:** 68

I am as eager to learn on this and other boiler related subjects as anyone, so am not intending to refute anyone's comments. I simply want to relate something I observed a few years ago with regard to traction engine boilers. I happened by chance on some folks operating a traction engine for an impromtu demonstration. Members of the public were being allowed to operate the engine. On a steam locomotive, as everyone reading this board probably knows, if you have a heavy hand in yanking open the throttle, you will probably spin the drivers which while bad form and adding wear to the tires is not immediately destructive to the engine or boiler. I observed that on a traction engine the same lack of finesse results in the front wheels of the engine lifting off the ground a few inches to as much as a foot and then with a considerable thud they drop to the ground as the engine takes off moving forward. I observed this repeated several times. As this engine was one of the type mentioned above with the front axle mounted to the bottom of the smoke box with no additional frame for support besides the boiler barrel I was struck by the amount of external abuse this boiler was subjected to. Hey, for all I know the boiler was substantially over engineered as a boiler goes for it's working pressure, and quite capable of withstanding this kind of abuse. I asked one of the operators if they had the boiler inspected or had hydro'd it and got a reply along the lines of "well my friend Billie-Bob and I looked in the wash out plugs and it was jest fine". Later I observed that they couldn't start the injector and were arguing over whether the water was low. I decided at that point it was time for me to head on down the road, and hope I didn't read their obituaries in the local paper.....

jim templin · **Posted:** Tue Apr 06, 2010 9:49 am

Mr Bane points to a substantial truth...any boiler can be subject to a fool. In Texas, YOU CAN NOT legally operate a power boiler without first having it completely inspected. If it is an historic boiler, that involves UTs, visual, calculations based on UT, and hydro. There are some of us that would like to see operators licensed as well. If you have been in some dry cleaners in very public places, and seen LWFCs stuck together with JB Weld, you would understand even more than seeing wheelie popping rednecks.

I will say that all of the traction engine owners I have been fortunate to know would have been rightfully horrified at what you saw. Any body that treats an extremely expensive antique that way is a complete idiot.

The only defense against an idiot is distance.

Mark Jordan · **Joined:** Fri Nov 07, 2008 11:21 am **Posts:** 490

Mr. Bane,
While this thread is not aimed at traction engine issues, I thank you for your post, and echo Jim Templin's remarks. At any show that I've been to, there is a substantial safety committee in place to keep this type of behavior from existing. While we all do invite the public to be included if there is interest (to promote the preservation effort) all operators are still in charge of their engines, and behave accordingly.

Lifting the wheels of a traction engine is not tolerated.

Thanks,
Mark
(traction engine owner)