streamlined locomotive

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(via New York Central 4-6-4 Hudson, J3a class, streamlined art deco steam locomotive # 5451, was designed for the 20th Century Limited, and is seen in the roundhouse at Harmon, New York, 1940 | Flickr - Photo Sharing!)

STETHACANTHUS

Sharks have an extraordinary evolutionary record dating back over 400 million years. They have been an eyewitness to evolution in the seas and still patrol waters all over the globe today. 

Stethacanthus, otherwise known as the ‘ironing board shark’, first appeared around 380 million years ago during the Devonian period and continued to thrive for the next 60 million years. Stethacanthus mostly had an outline similar to modern sharks although they had a distinctive anvil-shaped dorsal fin with small sharp spikes covering the crest. The function of this odd fin is unknown but it is only present in males, so it most likely played a role in courtship and competition. 

Stethacanthus was a reasonable sized shark for its time, yet it was smaller in comparison to most modern sharks being around 70cm to a metre in length. Its size probably restricted its diet to fish, cephalopods and possibly even trilobites that inhabited the reefs. Stethacanthus also had other features uncommon in other sharks, the tail fin was almost symmetrical compared to most other sharks which have a larger upper lobe. They also had distinctive fin whips projecting from the pectoral fins. Once again the function of these fin whips is unknown as they are absent in modern sharks but they likely played a role in mating.
The small stature of this shark may give the impression that it was a agile, deadly swimmer but this is unlikely to be the case. The long fin whips and rough dorsal scales likely hindered streamlined locomotion through the water making them slow-moving.


Stethacathus is not only infamous for its strange morphology, but because a handle of fossils are so brilliantly preserved allowing us to confidently reconstruct the whole animal and even identify its sex. This is a rarity amongst sharks, usually only their teeth survive the tests of time as their bodies are composed mainly of cartilage which is quick to decompose after death.

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Rio Grande Zephyr at Milepost 670.5 by James Belmont
Via Flickr:
The Rio Grande Zephyr train No. 18 emerges from a relatively ‘flat’ 0.9% section of track at Narrows, entering a stiffer 1.92% at Mill Fork in Spanish Fork Canyon on Sept. 25, 1977.

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Six months and counting by Kevin Cavanaugh
Via Flickr:
IIRC it took five sets of equipment to cover the rotations of the City of Los Angeles/Challenger over the UP/Milwaukee Road between LA and Chicago. Here, are two of the five, meeting at Colton, CA on the Santa Fe’s Third District on October 4 , 1970. Eastbound train #104 behind E8A 926 is about to cross the SP while a somewhat tardy train #103 passes by on the adjacent main. #103 was due at San Bernadino straight up at 11:00 AM while #104 was to stop at 2:40 PM. Assuming the e/b was close to on time, this meet should have taken place somewhere between LAUPT and East Los Angeles. Oh well, my win….