WHAT IS “O” GAUGE?
Toy trains have been built to a variety of gauges since the 19th century. The largest have been abandoned because those trains took up so much room and hobbyists preferred creating realistic layouts with structures and scenery in the space at their disposal. The most popular gauge for toy trains is O (pronounced "oh"), with 1 1/4 inches between the rails. The rugged O and O-27 gauge (circles of track have diameters of 31 and 27 inches, respectively) trains produced by Lionel in the 1940s and '50s helped introduce millions of children to this hobby. Many of those youngsters, now grown up, still enjoy trains of this size. Hobbyists realize that the toys of their youth weren't scale models. Most of today's O gauge trains feature greater realism and can be described as scale, having been built to a ratio of 1:48. That means a 50-foot boxcar would be 12 1/2 inches long in O.