Introduced to the world in the 1930's, HO trains were born in an attempt to develop a more realistic model train then was currently being manufactured. Running on a realistic-looking 2 rail track system, HO trains offered a 2-part advantage over O-Scale trains: 1. the ability to put more trains in a smaller space, and 2. they were designed with a more realistic look that many hobbyists were looking for.

Half the size of O-scale trains (O trains were originally called Zero-Gauge and HO gets it's name from the german word for half-zero), HO trains are 1:87 scale in size and have been the train of choice in America since the late 1950's.