The photographer of this shot had a nice commentary to add to it:
riding the subway, emerging from the station onto the streets of NYC, walking and feeling the brisk air of winter.. the thrill and energy of the city is intoxicating.
I like the sense of motion conveyed with the blur of the train. Ever since I was a small child, I always found the edge of the train platforms a very scary place – I often dreaded my wild imaginings of tripping and falling onto the tracks or being pushed by some crazed lunatic in the way of a rushing train. Quietly I wait for the trains a safe five or ten feet from the edge.