On3 Gauge is physically HO Gauge (1:48th size relative to real), but the trains are modeled on narrow gauge train lines (the rails are closer together). This means that although O and On3 cars and locomotives are the same size, the trucks (wheels) and rails (tracks) are different between the gauges so they will not run on each other’s model railroad tracks.
The n in the On3 name stands for Narrow Gauge. Normal standard gauge in the United States, Canada and Mexico is 4 foot 8.5 inches between the rails. Any railroad with rails closer together is referred to as Narrow Gauge.
The 3 in the On3 means instead of 4 foot 8.5 inches between the rails, there is only 3 scale feet between the rails. Popular in mining and lumber railroads, the Rio Grand Southern, the Denver South Park and Pacific, the Boulder Northwestern and parts of the Colorado Southern were all 3 foot narrow gauge lines.
What is On3 Scale?
On3 O Scale
We started our design on the new O/On3 layout in September of 2018. The goal was to create a double decker or mushroom style layout. This style of layout has two working levels one at 34" above the floor and the other is 55" to 66" above the floor. The two levels have grades taking the trains from the upper to lower level and back again. We started by developing two completely different drawings. After a year of monthly meetings and drawing ideas, we settled on a design and started concentrating on one plan. The O scale layout was designed for people that have disabilities or may be confined to a wheelchair. What you see here is the fruits of our labor.
The design takes us back to the early 1950's in the Colorado Mountains. In the early 1950's steam engines were losing ground to first early generation diesels. By late 1955, the steam engine was virtually gone. On the layout, our trip on the standard gauge begins in Denver and makes its way south down the front range of the Rockies. At Pueblo, CO the train turns west up the Royal Gorge on the Arkansas River to Salida, CO where the Standard gauge train meets the Narrow Gauge.
A word on track gauges, Standard gauge is what we all see in our daily lives; it is 4' 8 1/2" between the rails. Narrow gauge would be 3' between the rails. 3' was used up in the higher elevation mountains because it was cheaper to build and could make much sharper curves. In the railroad town of Salida, a passenger could disembark off the standard gauge train to the narrow gauge passenger train. From Salida, a passenger had access to all of Southwest Colorado and down to Santa Fe, NM via the narrow gauge. There are several destinations on the narrow gauge in this layout.