Thanks, everyone! I find that about 95% of these wind up in b&w, which seems about right when I'm composing. Occasionally one has to be in color (#5).
A few notes - #3 has long been my personal favorite. If I ever actually make my daydream of a book a reality, this would be the cover.
The camera was on my shoe for #5 - couldn't bring myself to put it on the floor.
As far as the lack of people - it's all timing. Weekends and evenings, and then wait for those precious one or two minutes after one train leaves and before people arrive to wait for the next one.
I would love to see other subways from around the world - I've ridden a few, but never really taken any shots. Anybody want to add some?
Here's a b&w similar to #5
steve