Frank W. Arnold (1851–1917) was an American trade union functionary, lawyer, businessman, and government employee.

[2] In 1873 Arnold returned to firing a locomotive on the Chicago, St. Louis & Pittsburg, remaining in that position until the end of 1876.

9 of the Brotherhood of Locomotive Firemen (B of LF) in February 1877 and remained an active member of the organization for the rest of his life.

[1] While working on the railroad, he studied law in his spare time, passing the Illinois State Bar in February 1879.

[1] Arnold left the Commercial Club to take a position as examiner for the United States Interstate Commerce Commission, a job which he would hold until the time of his death.

Arnold's body was transported back to his native Columbus and he was buried at Green Lawn Cemetery, located just west of the city.