Vintage 1945 build Alco S2s still perform daily switching duties at San Francisco's Pier 90. The two remaining Alcos #23, and #25 spent a number of years stored and inactive. But now the table has turned, and the future for these two vintage work horses looks bright. On any given afternoon one or both of these machines can be found shuffling cuts of cars around San Francisco's Port. The sounds they make are music to any railfans ears.