Monday, August 22, 2011

In The Middle Of The Forest...

Updated 10 PM, PDT

While we were driving through the Willamette National Forest last week, my traveling companion was kind enough to stop to let me take some photos of this bridge:

Image credit: Cujo359

It's a bit amazing to me that those long, thin columns can support a train so high in the air on such a narrow trestle. Watching a 100,000 ton train cross one of these strikes me as a lot like seeing a high wire act.

UPDATE: As commenter Dougo was kind enough to point out, the bridge is actually in the Willamette National Park, not Deschutes. I've corrected that error. In my defense, the two parks are right next to each other, and the maps I looked at don't agree on where the boundaries lie. However, they all agree that the bridge is within Willamette NP.

Dougo also pointed out that this bridge is near a recent mudslide that took out the rail line that passes over that bridge in two places:
An aerial view of the slide showed that more than 1,500 feet of mainline track at milepost 551.5 was gone. The lower mainline section that the slide covered was at 3,300 feet in elevation, while the upper main line that the slide destroyed was 900 feet higher. In between was a mess of mud, boulders, and more than 700,000 board feet of uprooted old-growth Douglas Fir timber. Most of the timber was jack-strawed (strewn in a jumbled pile) at the bottom.

To say that the Frazier Slide’s devastation was dramatic is a huge understatement. Geologists investigating the site estimated that once the slide broke loose, it rode a cushion of air down the mountainside at more than 60 mph. The slide destroyed everything in its path. Trees on the edge of the slide showed mud lines 40 and 50 feet high on their trunks with all limbs and branches below that line sheared off.

Union Pacific Vs. The Mudslide (PDF)
Professional Surveyor reports the likely cause of the mudslide:
Union Pacific was doing much more on the track than simply cleaning and reconnecting it. To analyze the causes of the slide, they worked with geotechnical and hydrology consultants and asked the survey crew to locate monitoring wells and spots on the hillside where water emerged. The analysis suggested that the slide was caused by built-up groundwater. This information was incorporated into a model of the site and used to design large ditches and culverts intended to shed and drain water, hopefully heading off future landslides. Also, the newly laid track is farther away from the mountainside, leaving more room for water management structure as well as more rock in the rail bed.

Mountain of Mud
Which is yet another reason why geology is important for things other than drilling oil wells.

The reason the track was cut in two places is that it does a switchback to get up the hill that had the mudslide. Here is a map with the approximate area of the mudslide in brown:
Image credit: Background map by OpenCycleMaps, annotation by Cujo359

Click on the map to enlarge it. For a more accurate graphic, check out page 26 (PDF page 3) of the article quoted above.

This track is in the middle of a large complex of national parks, which from a logistical perspective means that it's in the middle of nowhere. The crews that repaired that track had to bring everything they needed, and since it was a national park, where they have rules about such things, they no doubt had to pack it out again when they were finished. As Professional Surveyor notes:
Site logistics were eye-popping. For example, at one time 200-plus pieces of equipment were all running at once in an area just 2,000-feet long by 100-feet wide! And the functioning train tracks on either side of the slide area were used to advantage: four 20-car "mud trains" (two on each side of the slide) equipped with self-dumping cars were used to haul sized rock (used as ballast for new rail beds) to the site and to haul away mud, which lay as thick as 30 feet over some portions of track.

Even something as basic as communication required serious effort in this remote, difficult location. Since standard cell phone service wasn't available, Union Pacific had a custom cell phone tower installed and issued special phones to every worker on the project. And to get around on site, in the midst of dozens of trucks, backhoes, dozers, and trains, Vallo and Platero typically walked, as their work kept them on the leading edges of the project, where footing was still uncertain. They did have access to a John Deere gator for occasional equipment hauling.

Mountain of Mud
It's a lot different from working near a major population center, where much of what might be needed at the last minute to do some unforeseen work can probably be obtained at a local hardware store or equipment rental place. Out there, if you need lunch you have to bring it, and anything you need to prepare it.

One of the reasons I find this interesting, and worth noting, is that while I was driving around Oregon there were a number of things I saw that would make that mudslide look like a spot of dirt. More on that later, perhaps. Meanwhile, this is yet another example of why maintaining infrastructure is not only important, but essential if we are to continue to use it. Nature never stops breaking things.

Thanks to Dougo for providing the correction and the links.


Dougo said...

This is the main north-south rail route between Oregon and California.

Correction: this site is in the Willamette National Forest near Eagle Creek Road.

A few years ago there was a major landslide that closed the railroad for many months.

Cujo359 said...

Thanks, Dougo. I've updated the article to fix the error. Thanks for the interesting links, too. I suspect that when most of us see a railroad track, we have no idea what's required to keep it in working order.