I am going to post one last time.

A comment. When I was firing I always carried my water high, preferably 2/3 to 3/4 a glass. (Only once I carried it too high and it was carried over and up the stack etc. The engineer had to go easy on her (and didn't say much) but we maintained time.) I always tested the water glass before we started out. When I was running I would prove the glass occasionally using only the middle trycock. If I had to use the third (bottom) gauge to make sure we had water I was not happy but said nothing if it was infrequent. Only had one fireman I did not trust and regularly kept testing the middle cock because this ass was too lazy/stupid to carry proper water. Had he gone low too often I would have said something unkind.

Enough about me. What I really wanted to say is this: Rather than worry about old wives tales let's concentrate on training firemen to fire properly and shop men to clean/test/repair appliances properly. And engineers and road foremen to work safely and monitor others.

Make Safety More Than Just a Slogan.

One more and I am done stirring the pot, I promise.

I started this thread with a technical question, but I am much more interested in the practical one of instruction that I raised a number of times following. I never raised the question "What do you do if the crown sheet gets red hot and if you put water on it will it make the boiler blow up?" I didn't ask that because I already know what the answer. The answer is, "Who cares. If you have already let the water drop so low for so long that the crown sheet is glowing red it probably doesn't matter what you do because you barely have time to do anything at all." Honestly, the most practical reaction to discovering a crown sheet glowing red hot is to say a prayer, tuck your head between your legs and kiss your ass good-bye.

However, I do want to take a look at a couple of the scenarios considered so far:

Remember, in all these scenarios the crown sheet is already red hot and could go at any minute....

Scenario #1
Problem: Coal burning engine has low water and a red hot crown sheet.
Recommened solution: "I would dump the fire."
Sounds simple, right? Who has had the pleasure of shaking a thick road fire off of 50+ square feet of grates? You don't "just" dump the fire. This can take 10 minutes or more. I can't imagine how long it would take to dump 100 square feet on a large locomotive. Remember, that crown sheet is glowing and not giving you much time. It doesn't take but a few seconds to flip on the injector and if doing that buys you a minute or two, it just might be what you need to save your life and that of anyone nearby.

Scenario#2
Problem: Oil burning engine has low water and a red hot crown sheet.
Recommended solution: "Pull the emergency fuel shutoff and breath a sigh of relief"
Don't forget the several hundred pounds of glowing refractory that line the fire pan and make up the brick arch. I am not certain that the heat radiating off of this will have the effect of increasing the temperature of the glowing crown, but I am sure that it won't do anything to help it cool down. Again, I would feel a lot better if the fire was out AND the pressure in the boiler was dropping. Best way to accomplish that? Run the injector.

Scenario #3
Problem: A locomotive has low water and a red hot crown sheet, regardless of the fuel.
Recommended solution: "Run like hell"
This may or may not save your life but certainly won't do anything to keep the boiler from going up. Your chances are better if you are Usain Bolt, but I don't know that even he can out run boiler schrapnel chasing him down at 1000 feet per second. Not to mention that by abandoning the locomotive in this scenario, you may be opening yourself up to all manner of civil law suits or prosecution for criminal negligence. I will let it up to you whether it's worse to be vaporized after you turn on an injector or wind up as somebody's boyfriend in federal prison.

These scenarios may all be a bit dramatic, but the point is that the way to avoid any of this is to keep the crown sheet from overheating in the first place. The only way to do that is by cooling it with water. There is a long time between the point of "Low Water" and an overheated crown sheet. Instructing firemen in cases of low water to turn on the injector really can't hurt much. It might buy the time needed to drop the fire, lower the pressure, cool the crown sheet or keep it from ever becoming uncovered in the first place. Let's face it, if the crown sheet starts glowing, it's really a crap shoot at that point anyway.

PR

All engines should have a badge plate in the cab showing where the low point of the crown sheet is and most that I've seen have placed the water glass where the bottom of the glass is 6" above the low spot. I've seen water glasses from the SR and some other roads that had some ferocious grades and they were longer and marked for those particular grades.
Another scenario to add to the above is to call your brother in law on the cell phone and tell him to come see something really special.
Know how to blow out the glass, try cocks, water column properly, if possible know the railroad and don't play catch up. Stay ahead of it as much as you can.
You are probably going to have one or two situations if you work on these things that will pinch the seat cover off the cushion. Has always been and will always be.

You mean THIS from upthread?

No, I had a different article but it sure seems to be from the same test. It saves me from diggin' through boxes in the basement though!

PR

I don't think a test done in 1868 on locomotives probably built in the 1840's proves anything. The boilers back then were made of wrought iron.

Good point! Any of the Sterling 0-8-0s left that we can conduct some tests on and sell tickets to the "event" ????

I think the water back then was different too. What year of engine would be relevant to this test? The main thing is that all you guys missed the point. For a preservation site, how dare the Pennsy destroy a loco instead of donating it!

Having read the original BLEVE thread on Smokstak, this thread, and another Smokstak thread about this thread (ain't the Internet just grand?), I think there are some scientific questions that could stand researching with regard to fire tube boilers.

The steam pressure gradients caused by normal boiler operation, under varying loads. One element of this would be to quantify the tendency of heavy steam consumption loads (including safety valve operation) to alter the level of water in a boiler--the load "drawing" the water level up. Also the pressure gradients caused by the rapid creation or removal of said load.

The pressure gradient of steam generated by water (at various temperatures) impinging on a bare crown sheet (with varying crown sheet temperatures).

Research involving material characteristics of steel plate reaction to one sided chilling at various heat points, up to and including plastic deformation.

I suspect a lot of the answers are out there, but not necessarily in places that a traditional boiler operator would be looking. If the research doesn't exist, then it would be a excellent project for future research.

Michael Seitz
Missoula MT

This shot is making the rounds of Facebook. No details given, but it is an impressive shot.

One thing I don't quite understand is that most (all?) of the tubes seem to be small and have the ends doubled over. Are these all superheaters? Would there be that many? Is this a water tube boiler?

They have the "hairpin" look of superheater elements on my monitor.

dave

That's what I meant about them being doubled over. I'm just surprised to see quite so many. Any idea what would blow out all the superheaters like that? It's pretty hard to tell but it looks like they may all be superheaters?

My guess is that they are actually shredded pieces of ordinary flue tubes, split, bent and twisted as they simultaneously tried to exit the smokebox. They appear to me to be way too small to be superheater tubes, and smaller still to be superheater flues. The boiler spilled its guts for all to see. Looks like the front flue sheet failed for reasons unknown on a railroad unknown.

Demonstrates why a steam locomotive must be operated and maintained with an excess of caution. Remember, that boiler on your locomotive is a mobile bomb.

IMHO, of course.

Mike

Looks like an AMC/Van Sweringen 2-8-4, and it barfed up its Type E superheater. Those are superheater units; the bands and unit supports are visible on many. Engine didn't even derail!

Howard P.