Steam locomotive explosions?

Neglected to mention yesterday that Trains published an article devoted entirely to boiler explosions some time in the mid-1990's.

Also, that Freeman Hubbard's Railroad had an article on the D&H Cobleskill explosion sometime in the early 1960's. That one occurred in 1940 or 1941, and the power was a new 4-6-6-4 turned out by Alco only about a year before. (Our thanks to Mr. Deezlfan for pointing out the inconsistency of the grade argument on this one)

H. Reid's The Virginian Railway has a subchapter devoted to the loss of 2-10-10-2 No. 800 at Stewartsville, VA in 1941, also covered in the Trains article. This one was in level-ground, low-speed territory.

Also, sometime in the late 1990's, a Pennsylvania tourist railroad near Gettysburg suffered a boiler failure. The cause was later identified as poor firing practice/neglect. Due in large part to the design of the boiler (see pg 22 of the PDF file), no one was killed, and the incident was the subject of a Trains editorial at the time.

Here's a link to the NTSB report on that one:

http://www.ntsb.gov/publictn/1996/SIR9605.htm

EDM5970 wrote:I don't mean to dis LCJ here, but low water alarms were something that came along relatively late in the steam era.

I readily concede that I'm no expert on steam locomotives. Most of my "experience" has been indirect at best -- involving listening to engineers, who had been steam firemen, talk about their experiences. Legends surrounding boiler explosions were often part of recounts about times past on the New York Central operations in New York State.

Personally, I wouldn't know a steam locomotive's low water alarm if I tripped over it. My low water experience translates into diesel engines shutting down for lack of cooling water -- a much more benign situation for sure.

H.F.Malone wrote:Nells, what you need is for the BF to "gift" you with a "Your Hand on the Throttle" at Valley RR in Essex, CT ... Drop some hints!!!!

Thing is, HE would jump in and take over!

OK, when does the water normally turn into steam, when it is in the cylinder?

And is what H.F.Malone saying that the water itself cools certain metal parts, and if those get too hot, things break, steam exscapes, and BOOM?
Without water, the fire heat heats metal instead of water? Does coal fire get that hot??

Wow...

As I understand it (subject to correction):

Water turns to steam (in the boiler) as it gets to 212 F (100 C). It can get hotter than that under pressure before it turns to steam. As long as there is liquid water on top of the crown sheet (which is over the fire) the steel will not heat much beyond 212 F (100 C). The steel is still strong enough to hold in boiler pressure at this temperature.

Expanding steam is allowed into the cylinders, providing the power that turns the drivers.

As soon as the liquid water is gone from the crown sheet (low water), the temperature of the steel sheet is allowed to increase well above 212 F until it gets to a temperature where its solid properties no longer hold (it bends, melts, cracks open -- thus reducing the pressure in the boiler suddenly. Then, super heated water vapor in the boiler turns to steam and expands very quickly -- exploding the boiler structure.

Kaboom!

Yes -- coal fires can indeed get that hot.

So lack of water is causing a lack of cooling, thus degrading the metal. Hmmm... and I thought metal was tough!

Look at it this way, Nells: When steel gets red-hot, a blacksmith can shape it with a hammer. When it gets much hotter than that, it melts and you can pour it into a mold. The plastic state of an uncovered crown sheet is somewhere in between.

Nells:

If the BF gives YOU the VRR's "Hand on Throttle", then YOU are in the cab and HE is on the ground, waving and taking your picture as YOU go by him...that's the way it works there. He can't just "jump in" if he has not already signed up. It's YOUR hour to enjoy.

Give it a try; they will not only answer all your questions, you'll get to see and experience the steam loco in all it's dimensions--sight, sound, smell, feel, etc.

And, no, I don't have any interest (financial or otherwise) in VRR; but I was a fireman there once upon a time. And knew Kurt Ferris, too.

NellsChoo wrote:OK, when does the water normally turn into steam, when it is in the cylinder?

And is what H.F.Malone saying that the water itself cools certain metal parts, and if those get too hot, things break, steam exscapes, and BOOM?
Without water, the fire heat heats metal instead of water? Does coal fire get that hot??

Wow...

Water normally turns to steam *inside* the boiler. There are a whole lot of boiler designs and operating principles that have been used in ships, trains, and stationary engines over the years, but in general all of them generate steam within the boiler itself, and then deliver it to the working cylinders or turbines. The delivered steam can be "wet" or "dry." "Dry" steam is 100% water vapor, no droplets of liquid water at all and is the norm in high power/high efficiency steam engines. Steam can also be superheated well beyond the boiling point at the pressure inside the boiler (and by the way, since the boiler operates at high pressure, the water doesn't boil until WAY above 212 degrees F! Even car engines, which operate their cooling systems at a pressure of only about 15 PSI, will not begin to "boil" untill around 240 or 250 degrees F. Superheated dry steam is invisible if it were vented to the air- at least for several feet until it starts condensing. I've heard an engineer from a steam ship say that a dry steam leak could cut a broom handle in half instantly and never actually be seen- imagine what it could do to a person!

As far as "cooling" the metal- well, the metal is there to guide and contain the water as it is boiled into steam, and then guide the steam out of the boiler. The heat from the fire must flow through metal in order to reach the water and boil it. The metal is always balanced between the heat of the fire and the cooling effect of the water, and can be damaged by being "starved" for feedwater, or in some cases by being subjected to too large an inrush of cold feedwater which causes a sudden contraction of the metal.

Steam power is both art and science, and not nearly as simple as it might seem!