A model train's "scale" is the relationship between its size and the size of an actual train. "Gauge" is the distance between a track's rails. In model railroading, beginners sometimes use the terms “gauge” and “scale” interchangeably. Serious modelers are careful to use the terms correctly.
1 Scale (One Scale) - 1:32
Gauge: 1.75” (45mm)The numbered designation "1 Scale" dates back to before the turn of the 20th century. Although nearly forgotten after World War II, #1 scale regained some popularity in the UK as far back as the 1960s, and is experiencing a renaissance today in North America. The major model train manufacturer MTH is one of the new sources for modern #1 scale trains in North American prototypes.
T Scale = 1:450
In January of 2008, KK Eishindo Co., Ltd. of Japan introduced T scale. The "T" stands for three millimeters, which is the gauge of the rails. Initial offerings include West Japan Rwy. Co. trains in 4 color schemes and East Japan Rwy. Co. trains in 5 color schemes.These T scale train sets are listed at 5,250 yen ($52.85 US at the time of this writing). A basic oval of two-track rail with transformer, and accessories (including railer) is also 5,250 yen. That makes a starter set around $105.00, which is certainly competitive with other main stream scales.
KK Eishindo Co. is also offering a full line of T scale buildings, cars, and overhead lines.