Celebrating its 100th anniversary, REA issued postcards showing the transition from horse-drawn coaches to airplanes. The bulk of their shipping was done by rail, usually in their own express cars coupled to passenger trains. REA was formed in World War I when the U.S. government consolidated seven shipping companies (one of which dated back to 1839). Later it became a private multi-railroad-owned operation. Flanking the postcard above are two 1939 shipping labels.
Express offices were at virtually every railroad depot in the U.S. REA maintained a fleet of trucks for delivery and pickup of larger items.
For more information, go to http://www.wow.com/wiki/Railway_Express_Agency