HO scale (1:87) made its first appearance in Europe before becoming popular in the United States in the mid-1930s. The abbreviation “HO” stands for “half-O.” The smaller trains were less expensive and took up less space than their larger O scale cousins, which became popular with people who were moving into small homes and apartments in the 1940s. As manufacturing methods improved after the second World War, HO scale trains became popular for their finer detail and wide range of available accessories. The widest variety of trains are available in HO scale from hundreds of manufacturers in all price ranges.
From: Railroad Model Craftsmen Magazine December 25, 2016