[Image: NYC’s “track geometry car,” via Wikipedia].
The MTA‘s “track geometry car” slides around through the New York City subway, employing “a variety of sensors, measuring systems, and data management [software] to create a profile of the track being inspected.”
It’s a large-scale, precision optical mechanism, measuring such things as track curvature, alignment, “crosslevel,” rail gauge, warp, and more, using GPS, gyroscopes, proximity sensors, now-obsolete analogue measuring wheels, strain gauges, accelerometers, and even a “paint spray system” for marking “the location of a defect on the track once a defect is found.” These devices can be used in tandem with “ultrasonic rail-flaw detection vehicles” that use ultrasound “to ‘look’ inside rail to detect flaws unseen by the human eye. An internal flaw may be caused by a poor casting or metal mixture.”
But it’s hard not to be captivated by the idea of some blindingly well-lit behemoth vehicle maneuvering around beneath the city at night, all lasers, mirrors, lenses, and prisms—a surreal, moving garden of repurposed photographic equipment and motion-capture technologies from different historical eras—scanning the geometry of the metropolis from below, down to thermal flaws in the very metal it passes over. Surrounded by overlapping holographs of infinite lines and tunnels, like the subway dreaming of itself, this collage of physical instruments circles around and around through the foundation of the world, a two-track mind, a mobile neurology thinking in well-measured bursts of strobe light.
(Thanks to Nicola Twilley for the tip!)
6 thoughts on “Two-Track Mind”
They also pay guys to just sit on the subway and listen. These experts just ride around, listening to the clack clack of the subway, the screech of turns, but with an expert ear.
I sat next to one and talked with him – he pointed out a sound I barely noticed and told me that meant a rail wasn't level. He'd report it in and someone would come out to check that section.
I wish he had dressed as a fake commuter, with an empty briefcase and an ersatz suit, so he could blend in better…
How cool is that. Now I want to be a "subway whisperer" and get my own TV show.
I once worked on a similar system. It sits between the rails, looking upwards at the train wheels and reports any defective train wheels, or hot 'stuck' brakes.
They had to disguise them because drivers would see it and think it was a body on the rails and pull the brake.
I'd love to know the story of their putting all that together. It'd make a nonfiction book!
This article was tweeted by Jad Abumrad and he excerpted part of that third paragraph. That kind of speculation is the thing I love most about Geoff's posts. "Like the subway dreaming of itself," indeed.
Thanks, Christopher—good to see you around here, as well.
Matt, that's an amazing anecdote and something I would love to learn more about. Traveling around with those guys could make for an amazing radio segment someday.