Keywords: 1878 B&O.jpg http //upload wikimedia org/wikipedia/commons/thumb/3/33/1878_B 26O jpg/3512px-1878_B 26O jpg 50 PD-old 1878 Baltimore and Ohio Railroad map from http //memory loc gov/gmd/gmd370/g3701/g3701p/rr003400 sid shrunk to 50 Baltimore and Ohio Railroad maps |