I have many palm-sized sketchbooks filled with sketches of people reading, sleeping or gazing away on the subways. Here are some samples, pulled from recent and past travels. Occasionally, I have a sketch of a distracted friend in these books too.
I really like this one-- the rendition is very sensitive and echoes inside as if I was sitting opposite in the same subway car. I really get a feeling for the subject, although what I read into his expression is probably as much or more about me than about him. But that's so of all good art in which the craft brings out the content, explicit or implied. -- D.C.