Also a CTA (Chicago) train line, that runs between Skokie, Illinois and the northern edge of Chicago, Illinois

The line is interesting in that it only has 2 stations: Skokie (in Skokie...duh) and Howard (in the far north of Chicago). At Howard, one could transfer to the Purple Line to go north to Evanston or Wilmette or the Red Line to go into Chicago.

The Yellow Line, which is also known as the "Skokie Swift", runs Monday-Friday from around 5 AM-10 PM. Overnight and weekend service is replaced by a bus.

Travel time between Howard and Skokie is 8 minutes.

Source: and personal knowledge