I thought I would share this with the forum. The article this picture was attached to said boiler explosions were common during the days of steam. I am not sure it was that common. Especially near the end of steam. The designs were better understood near the end of steam.
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Ouch ! I wouldn't have wanted to be standing in front of that loco when it decided to regurgitate it's innards.
In comparison with derailments, head on/rear end collisions, bridge collapses, and telescoping, boiler explosions were rare.
Even in the old days, boiler explosions usually occurred less than 30 times each year.
Trains were NOT a safe way to travel in the 19th century...
Boiler explosions were not "common" in the steam era. They were very unusual and rare occurrences.
The photo you have posted is a rare failure of the front course. The vast majority of boiler explosions originated in the firebox, at the rear of the locomotive.
Wasn't the cause of most boiler explosions low water in the boiler? The low water would cause some part to overheat then melt or weaken.
Why would the saftey valve not go off and prevent the explosion?
TP Fan posted:Wasn't the cause of most boiler explosions low water in the boiler? The low water would cause some part to overheat then melt or weaken.
Why would the saftey valve not go off and prevent the explosion?
Safety valves keep the boiler from exploding due to the pressure getting to high and exceeding what the steel can handle. Low water allowing the crown sheet to over heat due to no water to cool it and then melt is entirely different.
"The days of steam" covers a lot of years. There was a reason that a boiler code was developed and implemented. Take a look at this testimony about the implementation of the "Locomotive Boiler Inspection Law"... I suggested scrolling up and reading pages 2567-2569.
In the era of modern steam, boiler explosions were certainly an unusual occurrence. In the early days of steam, however, they were enough of a concern that it led to the first Boiler & Pressure Vessel Code in 1914-15.
The Southern Pacific used "fusable boiler plugs" to prevent boiler explosions on most of their steam locomotives.
One l read about was that of one of the C&O's big articulateds at Hinton, WV. I think that was due to low water.
superwarp1 posted:TP Fan posted:Wasn't the cause of most boiler explosions low water in the boiler? The low water would cause some part to overheat then melt or weaken.
Why would the saftey valve not go off and prevent the explosion?
Safety valves keep the boiler from exploding due to the pressure getting to high and exceeding what the steel can handle.
Sorry, but safety valves do NOT "keep the boiler from exploding"! Just how could 3 or 4, 4" diameter devices allow such a catastrophic instantaneous increase in boiler pressure to escape from such an enormous pressure vessel, quickly enough to prevent an explosion?
Safety valves on steam locomotives are an audible & visual warning device used to prevent the Fireman from over-firing the boiler, and causing unnecessary higher stresses on the running gear. Safety valves at set for the maximum working boiler pressure, thus limiting the horsepower to the running gear machinery.
Low water allowing the crown sheet to over heat due to no water to cool it and then melt is entirely different.
Correct, and such a "human error" was the primary cause of boiler explosions on steam locomotives, "back in the day".
At normal atmospheric pressure water expands approximately 1760 times when it becomes the same weight of steam. Contain that amount of energy in a vessel, there is potential for a problem. Super heat the steam, even more energy. Recent picture at Steamtown. Repair required a new tube, 765, (Sept.,2015). So you can have a leak and still operate.
Lower tube, right in this picture. Note the angle piece of metal removed. 
Apparently all that water in the flue box creates considerable soot, dirt, and debris that had to be removed before the tube could be replaced.
Recent history, The Gettysburg tourist railroad had a catastrophic boiler failure due to low water and a crown sheet failure. The three people in the cab, Engineer and two fireman sustain serious injury from all the steam/heat and super heated water release back through the fire box. I believe the locomotive is at the Age of Steam facilities, Sugarcreek, Ohio. It remained in one piece. This failure prompted a lot of the regulations imposed on existing steam operations today. IMO. I could be wrong and often, Mike CT 
Here is one result of an exposed crown sheet, the boiler is completely blown off the frame:
Rusty
Assume these explosions like the one blown off the frame happen so instantaneously that the crew never knew what happened. No warning, then lights out 
.
Mike CT posted:Recent history, The Gettysburg tourist railroad had a catastrophic boiler failure due to low water and a crown sheet failure. The three people in the cab, Engineer and two fireman sustain serious injury from all the steam/heat and super heated water release back through the fire box. I believe the locomotive is at the Age of Steam facilities, Sugarcreek, Ohio. It remained in one piece. This failure prompted a lot of the regulations imposed on existing steam operations today. IMO. I could be wrong and often, Mike CT
Jack (Hot Water) could explain it way better than I, but the Canadian firebox design was the only reason the crew of 1278 wasn't blown to kingdom come. Still, they were all burned to some degree. It vented instead of flash-launching the boiler off the frame like a normal crown sheet failure would. I've seen recent photos of the interior of that boiler and it's downright frightening to see how far it'd sagged before it gave up. That operation was a nightmare of the 'Bubba' method of steam locomotive operation, as the NTSB report explains quite well. they only had one (apparently not working well) water sight glass and no running cab lights from the dynamo off the locomotive.
Hi P51, NTSB link seems broken. How about the whole URL link directly here?
rrman posted:Hi P51, NTSB link seems broken. How about the whole URL link directly here?
Well here's a scenario to consider...
Unlike stationary boilers, steam locomotives are moving vehicles (obviously) so the water does not stay level in the boiler when you're going up or down a hill. It is the fireman's job to know how to compensate for this and maintain a proper water level in the boiler no matter where you are on the railroad.
Consider this, you are on a level grade with a low amount of water in the glass (this shouldn't happen of course) and are approaching a downhill grade. Upon reaching that downhill section the water is going to slosh to the front of the boiler. If you haven't compensated for that downhill grade then there's a good chance the crown sheet is going to be exposed due to a lack of a proper water level. In normal operating conditions, the crown sheet and all firebox sheets are basically kept from melting by the water surrounding them. When exposed to an 1800 degree fire, they can heat up pretty quickly. If you start going up hill after the crown sheet is exposed and the water runs to the back of the boiler, or if any water sloshes on it for that matter from things like opening the throttle or adding water with the injector, it will flash to steam. As mentioned above, water expands over 1700 times in size when it flashes to steam. Trying to contain that amount of force with a sheet that has been weakened by fire is nearly impossible and was probably one of the more common boiler failures, and usually caused by operator error. Some explosions were caused by material failures, poor maintenance or other problems like that, but I think it's safe to say that many were operator error.
Mike CT posted:The Gettysburg tourist railroad... I believe the locomotive is at the Age of Steam facilities, Sugarcreek, Ohio.
Yes, CP 4-6-2 1278 is at Sugarcreek: http://www.ageofsteamroundhous...ves/cp-4-6-2-no-1278.
There was a boiler explosion on a traction engine in Ohio a few years back, though I haven't read much on the cause other than it also being crown sheet failure. More on that here and here with some aftermath photos here. I've been told this was fatal.
I was very surprised when I got a cab ride at Tweetsie RR several years back, on their Army 2-8-2 (yeah, I was crushed that I didn't get a ride on former ET&WNC 12 instead). Halfway through their run, they stopped for a 'indian attack' shtick, and I saw there was almost no water in the glass, something the crew said was normal for that exact spot where 190 was sitting. I took it that the reading wasn't correct as apparently the loco was teetering on where the water sloshed forward.
But how that didn't mean the crown sheet was exposed, I still am not clear on.
Here is a link to an incident report and photos of the boiler components from the tragic steam tractor explosion at a Medina, OH fair in 2001. Boiler explosions are not common things at all, as stated above. This particular accident was completely avoidable and was basically caused by operation of a boiler with excessive corrosion / erosion and thinning of the crown sheet and staybolts. The liability insurance for the event area's board was hitting the $80 - 100,000 mark in the years after the accident. Maybe others can shed some light on the state boiler regulations at the time. I think there was a gap in regs somewhere for antique boilers or similar.
http://www.dli.mn.gov/ccld/BoilerIncidentsHobby1.asp
http://www.dli.mn.gov/ccld/BoilerIncidentsHobby.asp
http://www.farmcollector.com/s...er-inspection-survey
p51 posted:I was very surprised when I got a cab ride at Tweetsie RR several years back, on their Army 2-8-2 (yeah, I was crushed that I didn't get a ride on former ET&WNC 12 instead). Halfway through their run, they stopped for a 'indian attack' shtick, and I saw there was almost no water in the glass, something the crew said was normal for that exact spot where 190 was sitting. I took it that the reading wasn't correct as apparently the loco was teetering on where the water sloshed forward.
But how that didn't mean the crown sheet was exposed, I still am not clear on.
I'm not sure if it's just a Michigan standard or not, or whether or not the FRA standards are different (we run under ASME boiler codes where I work since we're insular), but for us, the minimum legal distance from the lowest visible point in the glass to the top of the crown sheet is 3 inches. So it is possible for there to be water in the boiler to cover the crown sheet even if it's just out of sight of the glass, but I wouldn't be comfortable with that level as a fireman or engineer where I work. That being said, I'm not sure what your definition of low is, nor what the operating conditions of their railroad are like.
SantaFe158 posted:I'm not sure if it's just a Michigan standard or not, or whether or not the FRA standards are different (we run under ASME boiler codes where I work since we're insular), but for us, the minimum legal distance from the lowest visible point in the glass to the top of the crown sheet is 3 inches. So it is possible for there to be water in the boiler to cover the crown sheet even if it's just out of sight of the glass, but I wouldn't be comfortable with that level as a fireman or engineer where I work. That being said, I'm not sure what your definition of low is, nor what the operating conditions of their railroad are like.
Well, no water in the glass is a good definition of low, to me. But the crew said it was perfectly normal for that spot as they stopped there on every single run (and Tweetsie isn't known for antics of dumb operation), I assumed it was okay. But yeah, I was more than a little antsy until I saw water in the glass again once we got rolling...
p51 posted:SantaFe158 posted:I'm not sure if it's just a Michigan standard or not, or whether or not the FRA standards are different (we run under ASME boiler codes where I work since we're insular), but for us, the minimum legal distance from the lowest visible point in the glass to the top of the crown sheet is 3 inches. So it is possible for there to be water in the boiler to cover the crown sheet even if it's just out of sight of the glass, but I wouldn't be comfortable with that level as a fireman or engineer where I work. That being said, I'm not sure what your definition of low is, nor what the operating conditions of their railroad are like.
Well, no water in the glass is a good definition of low, to me. But the crew said it was perfectly normal for that spot as they stopped there on every single run (and Tweetsie isn't known for antics of dumb operation), I assumed it was okay. But yeah, I was more than a little antsy until I saw water in the glass again once we got rolling...
I believe all jurisdictions have a minimum distance between the bottom of the gage glass fitting and the uppermost part of the boiler. (Crown sheet or uppermost fire-side contact I guess) A water level that gently fluctuates a little is good; a level that stays stock still is extremely suspect - blow that glass out! I read a report years ago on an auxiliary boiler that blew out into the furnace during warm-up and badly burned the operator because the sight glass hadn't been checked. Reports of water level about the time of the incident indicated that the glass was half full but the connection was plugged and the actual level went low.
Old time rules stated that water level was checked not with the glass but with the gauge cocks. the glass was to be a visual back-up, but the rules requires the physical check of opening the valves to see whether there was water, a mix of water and steam, or only steam. Blockage of the line to the glass would be irrelevant in this case.
49 CFR 230.51 governs the location of water glasses:
"Every boiler shall be equipped with at least two water glasses. The lowest reading of the water glasses shall not be less than 3 inches above the highest part of the crown sheet. If gauge cocks are used, the reading of the lowest gauge cock shall not be less than 3 inches above the highest part of the crown sheet."
Three inches was also determined to be the minimum amount of water covering the crown sheet in the old catechisms.
Water glasses can be difficult to read for folks that don't have a lot of experience with them. Water can slosh several inches in either direction. Things like grade, movement of the locomotive, opening the throttle, etc. can all cause fluctuation. Just because YOU don't see water in a particular glass doesn't mean the crown sheet has been exposed (as noted above), although I personally wouldn't let it get to that point. When you're moving down the line, the water is constantly moving.
I never experienced a clogged water glass, but I ALWAYS checked the tri-cocks periodically and would occasionally blow down the water glass during the day. Even as an engineer.
Rusty
Rusty Traque posted:I never experienced a clogged water glass, but I ALWAYS checked the tri-cocks periodically and would occasionally blow down the water glass during the day. Even as an engineer.
Rusty
Exactly. We have a gauge glass and try-cocks on our locomotives. The try-cocks are nearest to the engineer on our locomotives so that's usually what I use to check on the fireman during the day mostly for my own mental note of water level in addition to his verbal communication.
Blowing down the glass is a pretty standard procedure, and not only can it tell if the line is blocked, but the valves have basically long metal rods on the end of them that are meant to poke through any obstruction. Typically our general rule is that the fireman blows it down first thing in the morning before doing anything else on the engine, and then at every crew change. When closing the drain valve, the water should rise up again pretty rapidly. If it's sluggish, or doesn't appear, then something is probably blocked or a bigger issue is present.
Back to the boiler explosions.... I talked to a couple of guys at the local fair with steam tractors. I asked about going down a hill and what type of brakes his tractor had.... He explained about the brakes and also mentioned they backed down hills. I assume to keep the water over the crown sheet?
I don't think any railroad grade would be that severe?
Mt Washington Steam engines were built for the step grade, and back down the mountain.
This is a very interesting thread! I'm learning a lot!
I remember the steam tractor displays at a tractor show in the summer in Greenville, Ohio, that came to a screeching halt after the Medina incident. The steam tractors were required to get their own grounds north of there, and l have not seen them advertised lately. Same for a big steam tractor show I've attended in Portland, Ind., not that far from there. Have not heard of it lately, either.
Wyhog posted:I don't think any railroad grade would be that severe?
For a 20 ft long boiler going up a 3% grade the front is over 7" higher than the rear.
For a 20 ft long boiler going down a 3% grade the rear is over 7" higher than the front.
The 7" difference between level and being on the grade is a lot, but the 14" water level difference when the loco goes from climbing a 3% grade to descending a 3% grade (or vice versa) is very significant.
arctan (7÷240) = 1.67°
240" tan 3° = 12.6"
have to say that 3° would be an extremely steep mainline grade.
Kelly Anderson posted:... Either learn what you need to KNOW, or stay out of the cab.
... or both?
Wyhog posted:For a 20 ft long boiler going up a 3% grade the front is over 7" higher than the rear.
The firebox would be considerably shorter than a boiler.
Mike CT posted:Mt Washington Steam engines were built for the step grade, and back down the mountain.
The Mt. Washington engines don't run behind the trains for boiler safety reasons--they do it to prevent runaways.
smd4 posted:Mike CT posted:Mt Washington Steam engines were built for the step grade, and back down the mountain.
The Mt. Washington engines don't run behind the trains for boiler safety reasons--they do it to prevent runaways.
I was referring to the angle of the boiler related to the track. Boiler angle is built to maintain level water during the trip up the mountain. Note the angle on your second look.
How and why do fusable plugs help to prevent boiler explosions?
pennytrains posted:How and why do fusable plugs help to prevent boiler explosions?
Briefly, because they melt at a certain temp. on the firebox side and extinguish the fire.
Kelly Anderson posted:PAUL ROMANO posted:pennytrains posted:How and why do fusable plugs help to prevent boiler explosions?
Briefly, because they melt at a certain temp. on the firebox side and extinguish the fire.
Or try to. In medium sized locomotives and larger, especially ones that are working hard, fusible plugs have melted and blown out without even being noticed by the crew.
Also, there is the limited useful life issue. Research has indicated that the tin in a fusible plug can transform into tin oxide in as few as five hundred hours of exposure to normal firebox heat, rendering it useless as a safety device. That was one of the glaring clues in the traction engine explosion in 2001. The crown sheet showed signs of being overheated, yet the fusible plug was intact. Even prior to that, it should have been apparent to the engine's owner in that the (used) fusible plug was brazed into the crown sheet (presumably because the crown sheet was too thin to seal with threads). The act of brazing it in should have melted the tin, but didn't, and the own happily ran the engine to his death.
I've seen the old instructions to "ensure the fusible plug is clean....", etc., but I've always thought a clean, effective tin surface would be gone shortly into boiler service time, as you say. It's always struck me as a last-ditch Hail Mary defence against a catastrophic event.
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