Wednesday, April 3, 2013

More Land-Use Oddities from the Mojave Region: The Tehachapi Loop

In yesterday's post, I was musing over the intense use of the land in the western Mojave Desert, in which we mine the land, the water and the air for resources we want and/or need. As we continued our drive west, I was reminded of one more historically significant use of the region: a transportation corridor. The town of Mojave is a crossroads, joining highways and freeways leading out of the eastern Sierra Nevada, Las Vegas and all points east, Bakersfield and the rest of the Central Valley, and of course Los Angeles.

The Sierra Nevada has always been a barrier to travel of all kinds: paths, wagon trails, roads, and railways cross the mountains in only a few places, and those few places present engineering challenges. No paved roads cross the mountains for well over 150 miles between Tioga Pass in Yosemite National Park, and Walker Pass well south of Sequoia National Park (Sherman Pass has a paved former logging road that is inappropriate for heavy traffic). The only freeways exist at Donner Summit and Tehachapi Pass, which is where we found ourselves on our recent trip.

I go over Tehachapi Pass several times every year, and on this trip I was looking for some more "short cuts" so we took Woodford-Tehachapi Road which winds its way across a ridge high above the main freeway for a number of miles before rejoining Highway 58 at Keene. The road provided wonderful views of the Southern Sierra Nevada and Tehachapi Mountains (above and below).
One cannot drive over Tehachapi Pass without an awareness of railroads and trains. As the only rail line between Los Angeles and the Central Valley, it is one of the busiest single-track mainlines in the world, averaging 40 trains a day. The rail line was constructed between 1874 and 1876, and as can be seen in the photos above, the engineering must have been a nightmare. The mostly granitic landscape is intricately eroded with steep slopes. Ultimately the tracks required 18 tunnels and 10 bridges. And still there was one spot that defied all normal efforts at maintaining the needed gradient. William Hood, the civil engineer who planned the route, hit on a unique solution. He built a 0.73 mile loop that gained the needed 77 feet. A 4,000 foot long train could pass over itself.
The Tehachapi Loop. The lower tunnel is in the cut on the left side of the photo
I have known about the loop for many years, and once visited the tunnel at the lower end, but unlike my railroad aficionado friends, I never realized that there was a really nice overlook of the loop from higher up on Woodford-Tehachapi Road. That's what I discovered on my trip the other day.
 I've since found out that the high-speed-rail system planned for California will utilize Tehachapi Pass. It will be interesting to see where they put the tracks for the HSR, and it will be especially interesting to watch a train climb the pass at more than 100 mph. To my train-lover friends: will that be possible? Just 31 minutes from Bakersfield to!

1 comment:

Gaelyn said...

I love to drive the Tehachapi road but didn't know about the loop in the train tracks. Pretty darn smart. That might prove a little difficult at 100mph.