N scale trains have existed in some form as far back as 1927, but they are one of the most recent of the model train sizes. Due to the prevalence of other scale trains that had been around longer, N's did not become popular and begin to be commercially produced until 1962. They were, however, one of the first scales to start out with recognized standards. In the early 1960's standards were agreed upon among manufacturers with respect to the voltage to be used, the track gauge, the train height, and other aspects of the scale. Before manufacturers around the world agreed on standards, buyers could not be assured that an N scale train from Marklin in Germany would fit on the same track as an N scale train built by Bachman in the US. Even today with standards, there are variants. These include 1:150 or 1:160 in Japan, and 1:152 in the UK among others.

N-scale trains grew to become the second most popular standard in the world. Only HO scale is more popular. N-scale takes less floor area than HO scale and so is used much more in locations where space is limited. N-scale's popularity is partly because its smaller size allows for a greater number of trains and much more expansive scenery in a given space. The scenery is also usually more detailed. The proliferation of N-scale has grown at varying rates in different countries. The rise in popularity of any type of model train often depends on people producing train models that are similar to the actual trains of the region. Since N-scale is one of the newest scales, it has taken longer for models that reflect local trains to be produced in some countries. In Japan, where space is limited, N-scale became popular rapidly and indeed is the most popular scale today, while in Australia it has taken a longer time to become more accepted.

For various reasons such as modeling narrow gauge (N scale train on HO gauge track), modeling minimum gauge (N scale train on a T scale track) or modeling perspective (N scale train in HO scale scenery) not all N scale trains are run on N gauge rails. These scales have been given their own letter designations in order to distinguish them from a totally N scale layout. Actual narrow gauge N scale tracks are around, but are rare due to a dearth of parts suppliers. N scale trains look rather small, (and at 1:148 of full scale, they are approximately half of HO scale), but they are not the smallest scale that is produced. Both T (1:450) and Z scales (1:220) are a lot smaller. If you would like your layout to fit in a smaller area, but still have heaps of detail or would like to have extensive scenery, N scale trains might be your best choice.