Good questions. I'll bet many don't know about them. The Ashcan Artists were American artists who worked about 1900-1910 or so. They were often newspaper illustrators who reflected the seamier side of life (in contrast to the more elegant and upper class American Impressionists). You could even say they reflected the influx of immigrants of the time. There were led by Robert Henri, who had studied in Germany and used rather dark colors. John Sloan painted pigeons and the NY El. Lawson used somewhat brigher blues.
Here is a landscape by Henri and a portrait by him.
John Sloan's Hairdresser's Window is below. Not a great image of it, but you get the idea.
