CLASSIFICATION. Locomotives are classified according to the number and arrangement of their driving and truck wheels. The various classes and the service for which each is chiefly employed are as follows: American or eight wheeled locomotive: this type of locomotive bas two pairs of driving wheels with a four-wheeled truck in front of them and is employed chiefly in passenger service. Atlantic locomotive: this type of locomotive consists of two pairs of drivers, a four-wheeled leading truck and a pair of trailing wheels. and is employed exclusively for high-speed passenger service. Mogul loco motive: this type of locomotive has three pairs of drivers and a pair of leading wheels, and is used for heavy freight service and to a consider able extent for passenger service. Ten-wheeled locomotive: this type of locomotive has three pairs of drivers and a four-wheeled leading truck, and is employed for heavy and high-speed pas senger service. Consolidation: this type of loco
motive has four pairs of drivers and a pair of leading wheels, and is used exclusively for freight service. Decapod: this type of engine has five pairs of drivers and no truck-wheels, and is used as a pushing engine on heavy grades and for very heavy freight service. Mastodon: this type of engine has four pairs of drivers and a four-wheeled leading truck. Switching: for switching purposes engines having either two pairs or three pairs of drivers are used and are known respectively as 'four-wheeled' and 'six wheeled' switchers. Forney: this type of engine has two pairs of drivers placed well forward and a four-wheeled trailing truck. and is used for suburban passenger and elevated railway service. There are several other types of locomotives in limited use, but those named are the standard forms.