The CORP (former Southern Pacific) passes through Jackson County, Oregon, including the communities of Phoenix and Talent. The effect of recent wildfires in the area can be seen here: https://www.youtube.com/watch?v=56iXfglDCGo
On another forum there has been speculation that CORP will need to replace burned wooden ties. Question: when wooden ties burn, does the heat cause metallurgical damage to the rails, switches, etc.?
In most cases, no. There might be damage to the hardness of head hardened rail but I am not familiar with how that is done. The wear resistant parts of switches and such are usually manganese steel which is not heat treatable.
For what it's worth...
When I was working in the gun business it was axiomatic that if a gun ( rifle, shotgun, pistol) was in a housefire, and the fire was hot enough to burn the stock away, the temper of the gun steel was considered ruined and for safety's sake the gun should be scrapped.
What a fire hot enough to burn away wooden ties would do to rail steel I wouldn't know, but it certainly wouldn't do it much good.
In a well constructed track the ties would be encased in the ballast structure. While it would not be impossible to have the ties catch fire - only the top surface of the tie is open to the air and sparks. The ballast structure should not have weeds and other agricultural growths able to catch fire. If ties were to catch fire it is possible enough temperature could be generated to play with the heat treating and tempering of the steel.
In any event, qualified MofW personnel would have to make a full inspection before train traffic would be restored.
Never too old to have a happy childhood!
We need to hear from someone who knows, but I've wondered before about the temper in steel rails when thinking about the white-hot thermite welds. I would guess that the temper is not something that is depended on for hardness or toughness. We had discussions years ago about NOT using a torch to burn holes in rails, apparently because of stresses set up in the steel, but in that case you have a local hot spot in relatively cool rail. When applying a thermite weld the rail in the vicinity of the weld is preheated so there is no sharp hot-cold boundary. Anyway, my point is that I would guess that temper may not be a factor. Again, we need to hear from someone who knows. (Calling Mudchicken.)
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"A stranger's just a friend you ain't met yet." --- Dave Gardner
Depends how hot the fire was, how old the ties were and condition of the joints (lots of popped bolts etc - If you had weber joints with wood inserts, you are buying lots of new OTM)....Cimmaron Valley Railway had over 60 miles of track burn not quite 10 years ago (it appears they managed to save a majority of the rail, but they had severe OTM issues, especially joints and anchors from what I was told)
Thanks, MC. But I'm still trying to figure out what "OTM" is.
Slightly off topic. Are loco air filters able to handle all the smoke and debri or do they have to be changed more often?. How many different air filters on a modern loco these days ?
Paul of CovingtonBut I'm still trying to figure out what "OTM" is.
A Weber joint is an odd kind of heavy wood reinforcement fishplate, used predominantly on ATSF. It is not meant as an insulating joint; it holds the rail ends in alignment while absorbing vertical shock and keeps tension on the rail-joint bolts. If you burn track containing these, you will need new joint bars -- perhaps a lot of them -- and probably different bolts and nuts and washers, all of which are supplied as OTM...
Thanks, O. I'd never heard of Weber joints, and I'm surprised that wood was used for that purpose.
Buried in another thread is the original patent and some of the sordid history of the damned things. The wood was supposed to expand and keep the joints tight and rattle-free. Nobody tested the concept first. Failed miserably.
Out here in the arid west and southwest you will find them on low tonnage branchlines and in yards/backtracks. They are a labor intensive headache to maintain and replace. Funds the roadmasters rarely got to use to replace them vanished post-WW1 when it became obvious Webbers were a failure. General policy became remove them as they failed or when you had to remove the bars for any reason. I inherited a pile of secondhand 90# bars at Walsh, CO when I moved onto a new territory from another roadmaster with no explanation. I soon figured-out why.
Thanks MC.
I'm still wondering about the concern Flintlock brought up about the temper of the steel in the rails themselves. Would the heat of the fire affect this adversely?
Temper: Given that most ROWs are kept reasonably clear of vegetation (clearly there's wide variations there), I'd opine that short of the ties burning, there would be little direct impingement of the flame on the rails. Just the usual ballast profile generally provides several feed of clear space.
Too, we have to consider the type of fire. If the fire is in dense underbrush near the ROW, there would be greater danger to the rails than a crown fire.
Another factor will be burning materials falling on the tracks themselves. If the ROW is kept clear (often 60-100' wide) only the taller trees pose that danger.
I think I'd be putting any rail from a burned wooden trestle in the recycle bin.
Lots of variables.
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...
What he said....
Work hardened rail is incredibly tough stuff. I have seen stuff from from bridge fires wind up in backtracks after audigage and magnetic/ultrasonic testing. Like Tree says, it's the decision after all the variables are considered.
(Conversely I tested some new 136# CWR over an inspection pit and found piped rail - removed that in a hurry and ticked off a CMO when his new new non-AREMA compliant toy was removed from service. Got in some hot water with my ChE for running the D-Car over the pit on a side trip.)
mudchicken and found piped rail -
Mudchicken, I always appreciate your posts for the knowledge they impart, but you sometimes use terms that puzzle me. Does "piped rail" mean that it contains hollow spots? (Like a pipe?)
I had to google that ...
rdamon I had to google that ...
That is bizarre, to say the least! Why would anyone make rail like that? It can't be as easy or as cheap as making conventional rail.
Maybe for running a well-insulated electrical cable through it?
Flintlock76Why would anyone make rail like that?
If there is a defect in the 'center' of the piece of steel being repeatedly rolled into rail shape, you will have what amounts to an open crack in the center of the web that comes under enormous mechanical and thermal stress as the rolling and annealing proceeds. I(f you then put this in track and load it, expect the two 'sides' to buckle, as seen here...
That makes sense! Thanks Mod-man!
The thing is, the "pipe" is so symmetical it certainly looks like it's an intentional feature.
And that's one of the reasons that the Sperry Rail Service (and others) send their detector cars across the country.
Well I was the first to reply to this and due to the oppressive moderation (I've only been subject to it for 10 years or so) the answer finally showed up 4 days later. I wonder how long this one will take.
Many have blathered about "temper" . Don't try to use words if you don't know what they mean.
When steel is hardened it is heated to a critical temperature at which it is no longer magnetic but austenitic. It is held there until this condition is fulldepth of the piece. Then it is "quenched" or cooled, usually rapidly depending on the alloy. his results in a change in the crystal structure to a harder version. It also results in stresses in the piece that are very undesirable. Obviously the outer layers cool first and fastest and shrink as they do so. So now we have a piece with hardness varying with depth and the outer layer stretched over the inner layers like a balloon. In extreme cases cracking willl occur within minutes and can sometimes be heard. To prevent this and relieve these outer stresses and promote uniform hardness the piece is reheated to a lower than critical temperature for a period of time. This is called "drawing" or "tempering". It is a verb, not a noun. The metal will have hardness, not "temper". The temperatures and times for these operations will be based on the manufactures recommendations and the heat treaters experience.
Steel that has not been hardened by heat treatment will not be damaged by any normal fire as the critical temperatures are above bright red and some approach white hot, 1300 to 1800 F. No wood fire in open air comes close.
Steel and rail in particular can work harden. As it is compressed and slightly bent by weight the surface will become harder. A temperature approaching a 1000F may relieve some of that but the process just starts over.
Rail cannot be terribly hard or it will break.
In short, steel can have hardness but not "temper". After years of service the surface can become hard, even brittle. No fire from ties in open air is hot enough to have a damaging effect on hardness. More serious would be a steel article that was unsupported for a distance as steel loses strength rapidly at 800F and it might sag under its own weight. This could possibly occur on a timber trestle fire.
tdmidget Rail cannot be terribly hard or it will break.
The operative concept is that the yield strength cannot be a too high of a fraction of ultimate tensile strength. A "soft" steel will have a relatively low fraction of yield to ultimate tensile strength and thus will plastically deform (yield) to relieve some of the applied stress. This is particularly important around cracks which introduce stress concentrations, a soft metal will yeild and thus relieve the stress concentration at the tip of the crack, where a very hard metal will not yield which then leads to deepening of the crack which then can lead to brittle failure of the metal.
The yielding process involves the creation and movement of dislocations in the crystal lattice, adding carbon to iron to make steel provides sites that trap the dislocations and thus prevent yielding (i.e. making steel harder). Similarly, the dislocations themselves can act as pinning sites, i.e. work hardening.
The above is a bit of regurgitation of my Intro to Materials class.
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