1.   As the early service winds down, crowds stream up the subway stairs, tumble from taxis.

2.   He had made the unwise choice of walking up the subway stairs with his hands in his pockets.

3.   One day, climbing the subway stairs, Lomando made up his mind to cut out the junk, but gradually.

4.   I still feel the steep descents in my knees every time I climb the subway stairs.