HO scale trains elsewhere were developed in response to the economic pressures of the Great Depression. The trains first appeared in the United Kingdom, originally as an alternative to 00 gauge, but could not make commercial headway against the established 00 gauge. However, it became very popular in the United States, where it took off in the late 1950s after interest in model railroads as toys began to decline and more emphasis began to be placed on realism in response to hobbyist demand. While HO scale is by nature more delicate than 0 scale, its smaller size allows modelers to fit more details and more scale track distance into a comparable area.