Toy Trains
A toy train is a toy that represents a train, distinguished from a model train by an emphasis on low cost and durability, rather than scale modeling. A toy train can be as simple as a pull toy that does not even run on track, or it might be operated by clockwork or a battery. Many toy trains blur the line between the two categories, running on electric power and approaching accurate scale.
Marklin measured the gauge as the distance between the centers of the two outer rails, rather than the distance between the outer rails themselves. Lionel's Standard gauge is allegedly the result of Lionel's misreading these standards, as are the variances in O gauge between the United States and Europe.
Most of these standards never really caught on, due to their large size, which made them impractical to use indoors, as well as the high price of manufacturing. Wide gauge trains, which are close in size to 2 gauge, are produced in limited quantities today, as are 1 gauge and O gauge trains. Of these, O gauge is the most popular.
