Columbia subject headings:
Baltimore and Ohio Railroad Company.
Willard, Daniel, 1861-1942.
Harvard subject headings:
Baltimore and Ohio Railroad Company--Biography.
Baltimore and Ohio Railroad Company--Management--History.
Baltimore and Ohio Railroad Company.
Executives--United States--Biography
Railroad engineers--United States--Biography.
Railroads--United States--Biography.
Willard, Daniel, 1861-1942.
Princeton subject headings:
Baltimore and Ohio Railroad Company.
Willard, Daniel, 1861-1942.