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Ups and downs

At the end of April we made another trip down to southern California to catch the tail end of the wildflower superbloom. We knew that the best part of the bloom had passed, because we had already seen lots of it a month ago, but thought that there might still be some color, especially at the higher elevations. Driving south, we chose to take a route down the eastern side of the Salinas and Central Valleys. It was a beautiful part of the drive, very much off the beaten path and blessedly peaceful and quiet.

Looking west, we could see how the marine layer had settled into the Salinas Valley, and the Santa Lucia Mountains beyond.

Salinas Valley
2019-04-27
© Allison J. Gong

We did see flowers, but the marvel of the weekend wasn't of the natural variety. We went into the Tehachapi Mountains and took a detour off the main highway to check out the Tehachapi Loop. The Loop is one of the marvels of railroad engineering (no pun intended).

On this trip I had only one lens with me, the 70-200 mm zoom. I had set myself the challenge of taking a road trip with just the one lens, knowing full well that I didn't have the proper equipment for any sort of wide-angle perspectives. It was fun learning how to work within the narrow parameters I had set for myself. However, it meant that I didn't have the ability to capture the entire diameter of the Tehachapi Loop, so I had to photograph it in pieces. Between 30 and 35 trains go through the Loop every day, and we were lucky enough to see one go down and one go up.

Here's the tail end of a train going up (clockwise) through the Loop. The two locomotives are pushing the train.

Tehachapi Loop
Train going through Tehachapi Loop
2019-04-28
© Allison J. Gong

Tehachapi Loop
Train going through Tehachapi Loop
2019-04-28
© Allison J. Gong
Tehachapi Loop
Train going through Tehachapi Loop
2019-04-28
© Allison J. Gong

Meanwhile, here's the front of the same train, being pulled by three orange locomotives:

Tehachapi Loop
Train going through Tehachapi Loop
2019-04-28
© Allison J. Gong

Loops like this one in the Tehachapi Mountains were invented to solve a problem facing railroads. Trains are a popular way to transport a lot of cargo over long distances, and are pretty efficient over flat terrain. However, mountain ranges are large obstacles, as trains can't go up or down steep grades. When railroad designers are planning rail routes, there are four options for crossing mountains:

  • Blast a tunnel through the mountains
  • Find a path that meanders through the lower elevations and doesn't get very steep
  • Switchbacks
  • Construct a loop!

I know that tunneling through mountains can be extremely expensive, perhaps prohibitively so. A long, meandering track that avoids the high passes can also be expensive to build, and would necessitate acquiring more land through eminent domain. Trains can't make sharp turns, which means that switchbacks would be impractical. That leaves the loop.

The actual spiral part of the Tehachapi Loop is is 1.17 km (=0.73 miles) long. Any train that is longer than 1200 meters (4000 feet) will cross over itself as it travels through the Loop. The elevation difference between the two tracks where they cross is 23 meters (77 feet). The Loop allows trains to gain or lose that elevation in a very short period of time (~5 minutes for the second train we watched) and relatively little track. It's a nifty invention!

Here's the video of a train going up through the Tehachapi Loop:

This whole train thing was so much fun to learn about, and to watch in action. I usually save my 'oohs' and 'aahs' for natural phenomena, but I was excited about this Loop. Maybe this is the time to discuss invention and teleology.

Innovation and invention occur in both the natural world and the human-constructed world. The main difference is that humans design and build things to solve some problem that exists--in other words, an object designed by people has a defined purpose. Think, I need something to scoop with, so I will hollow out a flat piece of wood and invent a thing that will some day be called a spoon. Whoever invented the spoon did so to carry out a specific function.

In the natural world, however, inventions don't happen because of some forecast need. Organisms have characteristics, some of which confer a slight advantage in survival and/or reproduction and are thus favored by natural selection. Incremental improvements sometimes occur, only because individuals with a minor change in some characteristic happen to leave more offspring than individuals without it. Over many generations, characteristics can change quite dramatically, but it is important to remember that the change is very slow. We must also remember that natural selection does not have foresight. Evolution doesn't operate so that organisms will be 'better' at some point in the future. Organisms evolve to survive in the conditions in which they live, not the conditions that their descendants may face some day.

In his book Climbing Mount Improbable, Richard Dawkins uses the term 'designoid' for biological organisms and their evolved phenotypes, to dissuade teleological thinking. This made-up word illustrates the notion that organisms may appear to be designed for their lifestyles and habitats, but the '-oid' suffix means 'sort of, but not really'. It is not by sheer chance that organisms appear to be suited for their environments, but neither is it by design. Natural selection does not aim towards an endpoint, or perfect goal. Populations continue to evolve at different rates, according to how quickly their environment is changing. But there is no forecasting involved.

Now that I've belabored that point to death, let's return to the Tehachapi Loop. It is both a very simple and very effective concept--that traveling in a spiral is an easy way to gain or lose altitude--but for some reason watching a train go through a loop and cross over itself was really cool. The Loop used to be open to passenger rail traffic via Amtrak, but regular passenger service over the Tehachapis ended decades ago. Every once in a while, though, Amtrak's Coast Starlight train is diverted to the Loop due to maintenance or construction along the normal route. I thought it would be fun to catch one of those trains to go through the Loop, until I realized that from the inside of the train it would just be like going through a tunnel. Passenger trains aren't long enough to cross over themselves where the Loop's rails cross, so there wouldn't be much to see. Oh well. I got to see two trains cross over themselves from the overlook, and that was super fun! Sometimes, being on the outside looking in is the perspective you want to have.

What do you think?

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