This locomotive was made by the Japanese company Masudaya founded by K.K. Matsutoku in Tokyo in 1923. Masudaya was a leading builder of mechanical and battery operated toys in the post war period, and unlike most of their competitors, has managed to survive to this day. Masudaya normally identifies their toys using the M-T, or Modern Toys logo. This object is a battery operated toy train designed to the old American style, as the Japanese were chiefly interested in the American market. These trains often featured an engineer leaning out of his cab, depicted by a small chubby boy based on the bright and breezy outlines, strong colours and simple shapes of cartoon characters. Masudaya was known for producing toy trains with 'funny faces' that magically avoided obstacles.

This is a Red Mountain train and there is also a Blue Mountain and Silver Mountain. The number '3963' is the manufacturer's serial number. Once the train is operating the boy driver moves from side to side and a whistling sound is made. This train is a relatively late version as it contains a lot of plastic parts.