Cajon Pass Fire

[Smike]

Got it

http://www.railpictures.net/photo/156602/

The wooden ties on the top deck burned away. leaving the concrete ties and rail to sag. Most likely the rest is fine.

[jmarley76]

I get to help fire a wood kiln at work for pottery, and the drier and smaller the wood, the faster the kiln builds up temperature. We fire to cone 10, which ranges from 2350-2380. Steel begins to melt around 2500, so it's not unreasonable that such a large fire could be that intense in spots.

I bet the whole thing gets replaced since the structural shift may have caused some damage.

[wazzou]

Got it

http://www.railpictures.net/photo/156602/

The wooden ties on the top deck burned away. leaving the concrete ties and rail to sag. Most likely the rest is fine.

Yep, it is a ballasted deck, so there would be a wood floor running the length of the span perpendicular to those stringers and the floor had sides to contain the ballast.

[nkalanaga]

If the wood was creosoted, you'd have an oil fire, which is hot enough to deform steel.  I'd be surprised if the tops, at least, of the girders aren't damaged.

[basementcalling]

News reports said 80,000 people evacuated from area's  32,000 homes in the danger zone, and the fire moved so fast fire crews didn't even get to try to save houses in some subdivisions that burned. Fire went from started to 42 square miles in area in less than 48 hours. Yikes.

Intense extreme wildfire behavior.

[Cajonpassfan]

No wood support structures here, all steel and concrete, see pic by Richard Steinheimer from way back when the Palmdale cutoff was relatively new. But of course the deck was probably wood.
Otto K.

[Missaberoad]

What would be the route for detoured traffic? Via the Coast line and Tehachapi? The Overland route? or is there a shorter route?
This is of course assuming it will be down for a little while and port of LA traffic must still travel...

[wazzou]

No wood support structures here, all steel and concrete, see pic by Richard Steinheimer from way back when the Palmdale cutoff was relatively new. But of course the deck was probably wood.
Otto K.

Otto, that photo appears to show the same ballasted deck configuration as the previous photo provided in the link. 
In fact, if you look at the photo closely of the burned out bridge, you can see where the ballast fell down below, seen on the tops of the concrete and steel piers.

[Cajonpassfan]

Bryan, i know, I was reacting to the reference to "wood support structures" in #617. The deck is/was of course wood.
Amazing the amount of heat that must have been generated. I'd love to get out there to see it, it's only a few miles for me, but the Pass is such a mess and emergency personnel have enough on their hands without having to deal with lookieloos. Sad, especially for those living and working there.
Otto K.

[Snark45]

Looks like steel doesn't need to melt to deform & lose strength due to heat. See here:

http://www.mace.manchester.ac.uk/project/research/structures/strucfire/materialInFire/Steel/default.htm

The temps mentioned are much lower than the melting point (800 C is about 1450 F). I first discovered this when reading the 9/11 damage analysis.  Regards, Harry

[GaryHinshaw]

Amtrak, however, appears to be rerouted via Mojave. There is a wye there connecting to the Creal Branch, so they have a way to turn shorter trains. Good thing, the Southwest Chief is a sold-out train all week

Indeed:  http://www.railpictures.net/photo/586200/

[nkalanaga]

Snark45:  You're right, and blacksmiths have used that for centuries.  Heat the metal and it can be worked well below the melting point.

A few years back one of the Cumbres and Toltec's  bridges had a tie fire which did a lot of damage to the girders.  So it doesn't take a massive wildfire.

[jagged ben]

Is this photo caption correct?  How is it that any trains could still have been running through this area yesterday?

http://photos.sbsun.com/2016/08/photos-the-blue-cut-fire-burns-out-of-control-in-cajon-pass-on-day-3/#56

[C855B]

Judging from the other pictures plus what I was seeing and hearing in other news reports, the fire turned west (Lytle Creek, Phelan, Wrightwood). Anything remaining in Cajon that hadn't burned yet amounted to small hotspots.

That bridge is going to be a pain in UP's side for a while. The crossover at Summit for contingencies is in the wrong direction in this case.

[Cajonpassfan]

Something I got from a local friend. Wow.
You may wish to turn down the sound, or not.
Otto K.

https://flipagram.com/f/uTcBO522XC

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