It could have been possible if the fireman or someone else in the cab opened the boiler blowdown valve. Steam locomotives had to be "blown down" periodically to clear sediments out of the boiler, and a boiler blowdown would have been exactly that way.
cacole It could have been possible if the fireman or someone else in the cab opened the boiler blowdown valve. Steam locomotives had to be "blown down" periodically to clear sediments out of the boiler, and a boiler blowdown would have been exactly that way.
It might also have been that the cylinder drain/blowoff cocks were opened to blow out any accumulated cylinder condensate. Don't know about the scalded part although if a person were close enough to the outlet it could happen. Live HP steam is hot.
Charlie
Chilliwack, BC
Unlikely, I've heard 3 or 4 stories over the years of engineers that got sick of being harassed that did this to discourage the offenders. Most recently, I think a story in Classic Trains within the past year or so told of an engineer that was fed up with the local hooligans throwing rocks and such at a schoolyard that bordered the rail line that did this and blew the boiler down.
He didn't scald anything to death, but he definitely discouraged it from happening again.
Cinematic license? We know that steam locomotives blow steam off horizontally. It may or may not be capable of scalding someone to death, but it does provide a plot device for the movie that is probably believable to the audience.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
You'd have to be pretty darn close for it to do significant harm. Generations of people used to walk right through the steam on depot platforms from the cylinder cocks just a few feet away.
I've seen the film. Psycho gangster Cody Jarrett shoots the engine crew, the fireman falls across the blow-down valve which releases the steam fatally scalding Cody's henchman.
I don't know if a fatal scalding is possible, but I wouldn't want to stand next to the blow-down pipe to find out! I've seen blow-downs in operation, also safety valves lifting, and they don't seem like places you want to be when it happens.
Cinematic license? Maybe, but to me it's believeable.
If I remember correctly, UP 844 was recently modified so that the boiler blowdown now releases roughly 300 psi steam horizontally. Perhaps the 'logic' involved in this was that the result would be no worse than the blow from cylinder cocks at starting.
I suspect that inhaling the live steam would produce death much more quickly than external scalding; it was my understanding that in cases of severe external exposure the nerves in the skin are killed off quickly but there is little injury to vital organs.
lenzfamilyIt might also have been that the cylinder drain/blowoff cocks were opened to blow out any accumulated cylinder condensate. Don't know about the scalded part although if a person were close enough to the outlet it could happen. Live HP steam is hot.
Vernon Smith in 'One Man's Locomotives' describes having his lower legs scalded badly from such a release. But this was while he was standing immediately adjacent to one of the cylinder cocks, with more than the usual amount of condensate in the cylinders.
Firelock76I don't know if a fatal scalding is possible, but I wouldn't want to stand next to the blow-down pipe to find out! I've seen blow-downs in operation, also safety valves lifting, and they don't seem like places you want to be when it happens.
I was riding the railroad at Greenfield Village in Michigan when they stopped "back in the woods" and blew down the locomotive. The steam plume had a pretty good reach. I wouldn't want to be there, either.
The white fluffy cloud you see exiting a steam locomotive isn’t steam at all, it is water vapor condensing.
Steam itself is invisible.
When released back in to atmosphere, the exothermic reaction causes the steam to give up energy to the surrounding cooler air almost instantly, and the water will condense, creating a visible cloud…unless you place your hand directly in front of the release valve, by the time you see the “steam cloud” the steam has given up almost all of its energy, (heat) to the surrounding air.
When you heat water to the boiling point it turns into a vapor, (what you see coming off the boiling pot of water on your stove is this vapor, some of which is condensing back into water) and by confining this vapor in a chamber or boiler and allowing the pressure to build, you create a gas, by then allowing the gas to escape under at a controlled rate into another chamber and expand, you convert the thermal energy of the steam into mechanical energy and can push a piston
As it expands after having lost some of the energy you added in the form of heat from your fire, and because it is no longer under pressure the steam gas becomes a vapor and begins to condense into water.
You can either scavenge that water vapor and re apply heat, or evacuate it to the atmosphere.
If you evacuate it, the moment it reaches ambient atmospheric pressure, it will complete the heat exchange, giving up all of its energy at once and condensing back into water vapor, the resulting vapor cloud is what we incorrectly think of as steam.
By the time you see the “steam cloud” the water has given up or exchanged all of the energy you applied in the form of heat from the boiler fire.
Because it is no longer at higher pressure than atmosphere and has given up almost all of its energy, the gas becomes a vapor and begins to condense back into water, it is below the boiling point of water, so depending on your location, say at sea level, it will be less than 212 degrees Fahrenheit, uncomfortable but not deadly.
That said, the vapor that will condense inside on the cooler cylinder wall will become liquid and be ejected along with the vapor, and that water can be close to boiling, which can cause injury.
As it expands even more, it gives up the last little bit of energy or heat, depending on the ambient temperature, the “steam cloud” can in fact, feel cooler than the surrounding air because of this exothermic reaction.
The “steam cloud” will vanish quickly, as the vapor completes the exchange of energy and returns to its liquid state, it becomes water again.
As water contacts your skin, you complete a thermal exchange, you “give up” some of your body heat to the water and hence, you “feel” cooler.
Oddly, steam is used in the refining process to cool a lot of the catalytic reactions used.
And, you home air conditioning system uses the same principle as a steam engine, just in reverse,(you are removing energy) in that you apply the heat from the air of your home to a gas, which carriers the heat outside to a condenser compressor system, which then compresses the gas to a liquid,, forcing it to give up the heat or energy it collected inside.
Go outside and place you hand over the big fan on you’re A/C unit and you can feel the heat or energy that was exchanged from the air in side.
The uber engineering guys here can explain the mechanics and process better, but if someone was scaled by a steam locomotive, they were within inches of the relief valve and were injured by water, not steam, by the time you see it, the steam part of the process is over and gone.
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Steam emitted directly from a hot up-to-pressure boiler blow-down will be dangerous within perhaps 20 feet or so, but it always depends on the exposure...which includes duration. I would not be averse to cylinder cocks venting near me from about 15 feet because it is so much less steam. The noise, on the other hand...either way, it's a problem.
-Crandell
edblysardThe uber engineering guys here can explain the mechanics and process better, but if someone was scalded by a steam locomotive, they were within inches of the relief valve and were injured by water, not steam, by the time you see it, the steam part of the process is over and gone.
You can have steam and condensation nuclei combined in a visible 'blow'. ('Vapor' per se is just about as invisible as steam, not getting into semantics of whether 'vapor' is 'steam' at ambient atmospheric pressure.) Only the nucleation as the steam begins to condense is visible; remember that as condensation occurs, heat (the latent heat of condensation, a very considerable amount) is given up to the surrounding environment, which would help keep the remaining steam/vapor invisible. Note that nucleate condensation in the cylinders is visible, at considerably above atmospheric pressure -- this is a phase change to water. This decreases the effective pressure in a cylinder, and hence the ability of the steam to do work, but does NOT reduce the temperature below equilibrium (or the ability of a given mass of 'exhaust' steam to produce tissue damage...)
The cloud of condensation nuclei, when it has reached temperature equilibrium with the surrounding gases in the atmosphere (which may not take all that long in seconds) is then just like a mist, and will absorb heat from surfaces (again, a considerable amount of heat) as needed to return to a vapor. This is not the same thing as an 'exothermic reaction' -- it is simple demonstration of thermodynamics.
Adding slightly to what's been said -- a large part of the damage from 'scalding' depends on the temperature. If you see visible condensation occurring, you'll be maintaining an equilibrium temperature of 212F for a comparatively long time. Now, tissue damage from contact with water at that temperature is what's commonly meant by 'scalding', but that's contact with a large mass of liquid that can transfer a large amount of heat quickly. "Condensed steam" at 212F is a finely-divided smaller mass (perhaps by roughly 1:1000, or whatever the effective condensation ratio is) so may require longer exposure to a given surface area to produce the same damage.
In the movie "The Train" the engineer of the armoured train blew the boiler down as a bunch of Germans were walking by. They were not happy. When I was in the Navy, there were several steam traps on heaters that were blowing by. The return water was dumped over the side and at the drain point there was always a jet of steam blowing out. I don't recall what was done to cure it, probably replace all the steam traps.
Breathing anything very hot can cause more problems than simple skin exposure. Your skin, up to a point, can heal, and take some time to do so. Searing one's lungs would be detrimental to life, as they need to function, properly, 24/7, so any damage would not be a good thing.
We encounter this a lot in the fire service. Victims who externally are more or less OK end up with severe airway damage due to breathing very hot air.
Pick your boiler pressure and read the temperature and see if you would want to be blasted by a boiler blowdown.
http://www.turnkeyips.com/assets/steam_temperature_pressure_table.pdf
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Interesting chart Big Jim. Like I said, I wouldn't want to be there when it happens.
Mind you, I've seen some rail videos where the engineer opens the cylinder cocks slightly as the locomotive passes a crowd at speed giving the folks a little "kiss" from the locomotive. That appears totally harmless, and the people seem to get a kick out of it.
BigJim Pick your boiler pressure and read the temperature and see if you would want to be blasted by a boiler blowdown. http://www.turnkeyips.com/assets/steam_temperature_pressure_table.pdf
Keenan and Keyes Steam Tables tell it all. When I operated we used them often enough.
I assumed (when I posted) nominal BP at 225 PSIG. Up close to the drain cocks would be dangerous for someone close by the cylinder outlet port. Boiler blowdown would be worse (usually greater volume plus right off the boiler and not an auxiliary) but I'm not familiar with locations of locomotive boiler blowdown pipe locations other than that they are usually at the lowest point of the boiler, on the firebox waterlegs somewhere most likely. They could blow sideways or straight down I suppose depending on the locomotive machinist installing or adapting same.
Live HPHT steam isn't anything to fool with even when being blown down or vented.
I've been there when it happens....daily and weekly....observing the results in the plant blowdown pit. I wouldn't want to be any closer than I was.
For what it's worth, I caught a You Tube video of a boiler and steam passage test on Southern 4501. Not too long into the video you can see steam (OK, it's the white clouds of condensate) roaring out of the cylinder and valve housings. NO-ONE is even remotely close to that end of the locomotive when it's happening. As a matter of fact the only people around are in the cab, or near it.
Search "You Tube Blowing out the steam passages on Southern 4501" and you'll see what I mean.
I think that says it all.
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