This is Starting Out After Rail by Thomas Eakins, c. 1874; the original watercolor hangs in the Wichita Art Museum. He produced the painting in oils as well. I had a very nice reproduction of this that I bought at the Goodwill. It had a Wichita Art Museum sticker on the back of the frame but for some reason my wife wasn't a fan so it ended up in a garage sale I think. I've often been sorry about that...