Derailed!

A train accident, possibly in Dutchess County, New York or thereabouts. The front bears the handwritten date "1920" in the bottom lefthand corner. The cardstock is Velox, a photographic paper invented by Leo Baekeland and manufactured by Kodak from 1902 onwards. The particular design around the space intended for the postage stamp indicates a date of manufacture from 1907-1914, so unless the handwritten date is wrong the card was printed on stock that had been sitting around for at least six years. It was never mailed.

As far as I can tell this isn't a commercially printed postcard but an actual photographic print on postcard stock. Vast numbers of these so-called "Real Photo postcards," which were produced with a specially sized film, were created beginning around 1902, as advances in photographic technology made it possible for amateurs and professionals alike, even in small towns, to document both ordinary life and newsworthy events and distribute the resulting images to friends and family around the country.

There are several excellent books that collect Real Photo images, including Rosamond B. Vaule's As We Were: American Photographic Postcards, 1905-1930, and, most recently, Luc Sante's Folk Photography: The American Real-Photo Postcard 1905-1930, which has just been published by YETI Books. Some images from the latter can be seen on the Artforum website.