[2][3][4][5] Dumaine began working for his father as an errand boy and eventually became the #2 man in his business empire.
Following the elder Dumaine's death in 1951, Frederic succeeded his father as president of the New York, New Haven and Hartford Railroad and the Amoskeag Company.
[2] In 1954, Patrick B. McGinnis won a proxy fight for control of the New Haven and succeed Dumaine as president.
[7] In 1962, Amoskeag sold control of Avis to Lazard Freres and Robert Townsend succeeded Dumaine as the head of the company.
[10] He resigned the following year prior to a vote on a merger with the Norfolk and Western Railway, which a majority of the D&H board supported, but Dumaine opposed.