Transcontinental Air Mail Route Arrows

[Grzrd]

This article discusses artifacts from a brief period in American history: large concrete arrows in the ground intended to assist air mail pilots in navigating their routes:

Every so often, usually in the vast deserts of the American Southwest, a hiker or a backpacker will run across something puzzling: a ginormous concrete arrow, as much as seventy feet in length, just sitting in the middle of scrub-covered nowhere. What are these giant arrows? Some kind of surveying mark? Landing beacons for flying saucers? Earth's turn signals? No, it's...
the Transcontinental Air Mail Route.
On August 20, 1920, the United States opened its first coast-to-coast airmail delivery route, just 60 years after the Pony Express closed up shop. There were no good aviation charts in those days, so pilots had to eyeball their way across the country using landmarks. This meant that flying in bad weather was difficult, and night flying was just about impossible.
The Postal Service solved the problem with the world's first ground-based civilian navigation system: a series of lit beacons that would extend from New York to San Francisco. Every ten miles, pilots would pass a bright yellow concrete arrow. Each arrow would be surmounted by a 51-foot steel tower and lit by a million-candlepower rotating beacon. (A generator shed at the tail of each arrow powered the beacon.) Now mail could get from the Atlantic to the Pacific not in a matter of weeks, but in just 30 hours or so. ....
Radio and radar are, of course, infinitely less cool than a concrete Yellow Brick Road from sea to shining sea, but I think we all know how this story ends. New advances in communication and navigation technology made the big arrows obsolete, and the Commerce Department decommissioned the beacons in the 1940s. The steel towers were torn down and went to the war effort. But the hundreds of arrows remain. Their yellow paint is gone, their concrete cracks a little more with every winter frost, and no one crosses their path much, except for coyotes and tumbleweeds. But they're still out there.

[ZLoth]

See this pre-existing thread. 

[Grzrd]

I totally missed the earlier thread.  Mods - please either delete this thread or merge posts into prior thread.