Illinois Central R.R., freight cars in South Water Street freight terminal, Chicago, Ill. (LOC), originally uploaded by The Library of Congress.

What a beautiful photo. If I ever own a bar, a big print of this is going over the bar.

You can snag a high res tiff from the library of congress here. It’s 7829×6081pixels, making it high rez enough to print posters and shit. Best of all it’s public domain for US citizens, since it’s a government document!