Hi everybody that remembers me. I got a free 20 minutes, so I thought I would put a musing that I had out there for you guys and girls to kick around.
Last issue of Trains had an interesting article about UP 844 or UP 8444 depending upon your rendition of locomotive etiology. Anyway, it was suggested that the reason for a prior boiler problem was the water the engine used in its excursion service. The article said something to the effect that city water that the engines use now days has more oxygen in it that water used from days gone by.
Anyone have anything to expand on that?
I remember when I was about 5 years old–25 years ago–and my father would take me for a walk on the railroad tracks (remember when we were allowed to do that?). At that point, the water tower for the old Wabash line was still standing and was hooked up to the city water line. I vividly remember my father explaining to me how a steamer would top off on it, and the city water line would automatically refill it.
The Wabash of yesteryear used city water, and I am sure this could not have been the only locale in the United States to have such an arrangement.
What is different in the oxegen levels of city water of yesteryear as compared to the oxygen levels of today? I am sure there is a rational explanation that I am not seeing–as the declarent of the article’s statement knows more about these things than I. But, I am kind of bemused by the comment that the water used by steam engines today has more oxygen in it.
I know that the Steam locomotive that ran between Cedar Park TX and Burnet used city water but they would add chemical to the water in the tender after filling to settle some of the solids and counteract some of the other chemicals in the water. Chlorine at higher temperatures can be quite corrosive - depending on what else is floating around in the water.
Most city water before it is put into the mains is put basiclly thru a fountain style device to arearate it for better place. That plus it helps get rid of some of the chlorine that is use since that does evaporate.
I don’t think the water was fluoridated but it had a lot of chlorine and also some ammonia to try to neutralize the basic ph. - but I think the dissolved solids were the biggest problem. I was riding the train out of Burnet one day and they had to stop the engine twice in the first 5 miles to blow the foam out of the boiler as it was inhibiting steaming. No steam - no go.
This goes back a VERY long time into my dark gray cobwebbed memory, but as I seem to recall, the problem is one of ionization. As the city water travels through it’s distriubution piping it becomes ionized (can’t remember if it becomes positively or negatively charged) but, then once put into the extreme environment of a boiler, it actually reacts with the metal in an acidic reaction, erroding the boiler from the inside.
I wondered if the age of the loco and the type of periodic usage also played a role. 844 has probably done more excursion miles than any other steamer and I’d guess it also spends quite a bit of time sitting in the roundhouse.
I really enjoyed that article and if any of the people involved in the rebuilding are reading, a very big THANK YOU.
Getting decent boiler water has always been a problem with steam locomotives – too much solids, dissolved or otherwise, and it foams like mad. Also, a good bit of the city water one finds can be astonishingly corrosive, either from high dissolved oxygen levels (if it’s been aerated, particularly) or from low pH or any of a variety of problems.
Getting good water was particularly a problem for the Santa Fe – and is one reason why they dieselised so soon.
Chlorine is also corrosive as it is also an oxidizer. Steel wool will burn with a flame in an atmosphere of pure chlorine – just a little slower than air. So imagiine what chlorine will do to the inside of a boiler.
Think in terms of clean drinking water standards imposed by state and federal governments. One thing that is probably done a lot more is aereation of the water, as that is supposed to be bad for certain bacteria. I don’t know how much of the dissolved oxygen would dissipate in a water tank (it’s been a zillion years since my last chemistry class) but I would guess that some of it would be gone by the time the steamer would come along for a top-up.
Maybe that’s why we get bottled water for drinking, or maybe it’s just because our tap water isn’t the most palatable down here.
Many, if not most, of the water tanks providing feed water to locomotive boilers were not connected to municipal water systems. This was only the case in cities and large towns. Since water towers were spaced fairly close togetheralong the rail line, there were a lot of them that weren’t in the cities.
Most of you probably remember the phrase “tank town” meaning a really small place with not much there. The name comes from rural locations which had a water tank for the railroad, a few buildings for the handful of inhabitants, and not much else. And by no means were all water tanks in towns. Some were out in the middle of nowhere.
What does this have to do with oxygen in boiler water?
Well, the water in these water tanks could be pumped from a well, flow by gravity through pipes from a nearby stream, pumped from a stream or pond lower than track level, etc. So, unless it were a particularly swiftly flowing stream, you’d probably have less dissolved oxygen than in today’s aerated municipal water supplies. Also, don’t forget that the water would be standing around in the tank for a long, long time. Tanks were designed to have enough capacity to hold several tenders worth of water. There would be plenty of time for excess dissolved oxygen to diffuse out of the water in the tank. If you think of the water tank as an artificial stagnant pond, you’d probably be fairly close.
By the way, I checked out the site that was mentioned by Mark_W._Hemphill:
Not only does it discuss deaeration, but you can access pages explaining the different mechanisms of corrosion, boiler water treatment, foaming and other topics. Thanks for the great link, Mark!!
Well, once they realized that it needed to be done, that is. For over a century they just filled 'em up and went (of course, a 1941 boiler costs a heck of a lot more than an 1823 boiler [:)]).
Water used to be carried in steel pipes, but not stainless steel. As it was distributed throughout urban areas, it interacted with the lower grades of steel in the pipes to make iron-oxides. This meant that oxygen atoms were bound to the iron, so the oxygen content in the water fell over time. This accounted for some of the phenomena that you describe.
Also, dissolved salts, like alkali salts, especially on the prairies, were highly problematic for steam locos, so they sometimes towed a second tender of better water.
Nowadays, ionizing chambers are used, including ozonators, to sterilize water, and yes, they also use aeration fountains to improve taste.