The Laramee Filter: pseudorandom thoughts, subsequently put on the Internet.
Tom Laramee
Date Published:
December 24th, 2016
Word Count:
585 (4:00 read time)
Filed Under:

I Believe I've Just Solved A 20-Year Old Mystery Of a Train Fire and Bridge Collapse

When i was an undergrad at UMass, one of my professors (Al Russell) told an anecdotal story about simple harmonic motion that went something like this:

"A railroad bridge across a river looked like it was going to be washed away in rising floodwaters, and so the town's engineers got together to see if there was anything they could do to prevent this from happening. One of the engineers hypothesized that, if they could make the bridge heavier, it would also be sturdier, which would give it a much better chance of surviving. The engineers came up with a plan to drive a train onto the bridge and then park/stop it, so it spanned the entire length of the bridge."

Seems like a reasoanble idea, yes? The 2nd part of the story was apparently to illustrate the concept that you should think your engineering decisions all the way through:

"Apparently, what the engineers did not consider was the periodicity of the bridge, specifically w/r/t the flood waters. The water induced simple harmonic motion in the bridge (and by proxy in the train). The coal in one of the coal cars was sufficiently shaken that it ended up catching on fire, which caught the rest of the train on fire, and also the bridge. If i'm recalling the story correctly, the entire train (and bridge) collapsed into the river."

The professor mentioned the name of the river, and even though the story had absolutely nothing to do with the class material at the time, I took a couple of notes, and wrote the name of the river as "Atufalaga" .. which was the best I could do phonetically.

Of course, with this name, I couldn't find a reference .. since it was misspelled.

(I even googled a couple dozen phonetic variants of the name but couldn't find anything)

I've always wondered if (a) the story was true and (b) what the real name of the river/bridge was.

(Fast forward many years)

I recently read a book called Strangers in Their Own Land, which is about why white working class voters vote against their own interests. The book focuses on conservative voters from Louisiana.

(Spoiler alert: the reason why people vote against their own interests is, summed up in a single word: "God")

On page 241, the author mentions the "Atchafalaya Basin" (which, interestingly enough, is susceptible to long periods of deep flooding).

As it turns out, there's also an Atchafalaya River (it is the fifth largest river in North America, by discharge).

There have been 12 bridges built over this river, ~five of them with train tracks on them, and two of the bridges are listed as "lost" (Krotz Springs Bridge, built in 1934 and SP - Atchafalaya River Bridge, built circa 1923).

After some creative searching, I finally found a reference to the original story .. in a 1987 issue of The New Yorker magazine. The title of the article is " THE CONTROL OF NATURE - ATCHAFALAYA:

"The crisis recalled the magnitude of β€œthe ’27 high water,” when Dugie was a baby. Up the valley somewhere, during the ’27 high water, was a railroad bridge with a train sitting on it loaded with coal. The train had been put there because its weight might help keep the bridge in place, but the bridge, vibrating in the floodwater, produced so much friction that the coal in the gondolas caught fire. Soon the bridge, the train, and the glowing coal fell into the water."

Mystery solved!

The mystery of whether or not i am a total dork: solved!