The card has no copyright markings on it as can be seen in the links above.
United States Copyright Office page 2 "Visually Perceptible Copies The notice for visually perceptible copies should contain all three elements described below. They should appear together or in close proximity on the copies.
2 The year of first publication. If the work is a derivative work or a compilation incorporating previously published material, the year date of first publication of the derivative work or compilation is sufficient. Examples of derivative works are translations or dramatizations; an example of a compilation is an anthology. The year may be omitted when a pictorial, graphic, or sculptural work, with accompanying textual matter, if any, is reproduced in or on greeting cards, postcards, stationery, jewelry, dolls, toys, or useful articles.
The author died in 1941, so this work is in the public domain in its country of origin and other countries and areas where the copyright term is the author's life plus 80 years or fewer.
{{Information |Description=Postcard photo of a Great Northern train leaving the Cascade Tunnel. the photo seems to have been hand-colored. |Source=[http://www.ebay.com/itm/3042-Vintage-Postcard-1924-Electric-Engine-Train-Cascade-Tunnel-Northern-Railwa...