[1] He started his career as a clerk in the auditor's office of the Vandalia Railroad at Terre Haute, Indiana.
In 1892, he was chosen as chairman of the Western Passenger Association which was headquartered in Chicago, Illinois.
In October 1911, he resigned from Lackawanna to become president of Wells Fargo & Co.[1] In 1918, he formed the American Railway Express Company, becoming chairman of the board while George Chadbourne Taylor became president.
[2][3] On December 3, 1884, Caldwell was married to Sarah Elizabeth Bowman (1860–1948), a daughter of Bishop Thomas Bowman of the Methodist Episcopal Church, who had served as Chaplain of the U.S. Senate during President Abraham Lincoln's administration.
[1] Caldwell died on September 24, 1922, in a stateroom aboard a Pullman train just before he reached Burlington, Vermont while he was on his way home from a fishing trip in Canada.