Back in 1992 I used to ride the subway with my Leica and shoot the passengers without their knowledge, although the camera was in plain view. This can be done with a rangefinder camera without much difficulty once you have worked out the settings and a bit of subterfuge. Walker Evans made a series of amazing subway photographs in the 1930’s with a hidden camera, producing iconic images that were published in a book, “Many Are Called” (http://www.npr.org/templates/story/story.php?storyId=4156233) . Somehow, although the subway is a very public place, people can be at their most unguarded on the trains. Look for more pictures from my subway series as I continue to scan my negatives from 20 years ago.