Some of the mechanical devices which have been introduced for more efficient handling and classifying of freight cars are auto matic switch control, car retarders and flood lighting. In some yards complete systems of centrally operated switches are used. These are electro-pneumatic, air being admitted by electrically controlled valves to a cylinder which throws the point of the switch. An operator in a tower throws the switches by pushing a button. An indicator in circuit with the rails of the switch shows on the operating board when a car has cleared the switch. Fur ther progress in classification yard design and practice has been achieved by the installation of car retarders which eliminate the car riders, reduce car damage and speed up operation. Car re tarders are often castiron shoes placed along both sides of each rail which when operated by electro-pneumatic valves grip the car wheels and reduce speed.
Studies of car retarder operations indicate that the classifica tion track grades should be decreased to between .2% and .3% so that cars entering the tracks will proceed at a speed of from three to five m.p.h. without accelerating or decelerating, and con tinue at this speed to the end of the track.
Flood lighting permits operation without headlights and switch lamps. The primary benefits are safety to employees, reduction of damage to equipment, and decrease of theft.
Less-than-carload Transfer Houses.—Freight loaded at smaller shipping stations or for less important destinations is stowed in local peddler or ferry cars, as they are known, and hauled to transfer stations at strategic junctions. At these inter mediate transfer stations the package freight is sorted and consol idated into destination cars or cars for transfer stations at more distant division points. Such transfer stations are maintained at important division points by all carriers handling any consider able volume of less-than-carload freight.
Delivery Terminals.—Yards serving a terminus are often located near important intermediate yards but have facilities for delivering freight which are not found in the intermediate yards. Delivery terminals are made up of team track yards, freight houses, and specialized freight facilities such as live stock yards, produce terminals and grain elevators.
Team Track Yards.—The ordinary method of delivering car load freight is at team track yards. Such yards are of various designs depending upon the size of the property available. They consist of stub-end tracks laid out in pairs with paved roadways between. Most team track yards are equipped with scales and with cranes for lifting heavy freight.
Freight Houses.—Numerous freight houses are maintained in important terminal centres for the handling of package freight in less-than-carload lots and sometimes in carloads as well. Freight houses have a driveway on one side accessible to trucks of ship pers and consignees, and rails on the other side. Often the inbound and outbound platforms face on separate driveways with four or five tracks between them. Many modern freight houses are con structed in two levels or more. In many stations the freight is un loaded by the shipper's teamster straight into wheeled trucks, manually operated or hauled by tractors. Where the volume of package freight is sufficient, cars are loaded to destination, other wise they are sent to the division transfer houses for reclassifica tion.
Produce Terminals.—Perishable freight, particularly the fresh fruit and vegetable traffic, has reached such a volume that special handling facilities have been provided in important delivery yards. In 1927 over one million cars of fresh fruits and vegetables alone were originated by the railroads of the United States. A typical produce terminal consists of a special section in the classifica tion yard for the purpose of holding and re-icing cars for con signee's order; a team track yard where cars are spotted along side narrow platforms permitting inspection of contents and reconsignment or local distribution after sale; and a heated freight house where display and sale of produce and consolidation of buyers' truck loads takes place. The newer terminals in New York, Philadelphia, Boston and Chicago provide space for auction rooms within the freight house.
Live Stock Yards.—The movement of live stock is an impor tant feature of railroad operation, particularly in the territory of Chicago and west. In the Kansas City, Mo., stock yards 7,000, 00o head of live stock are handled in a single year; at Chicago 15,000,00o. The Union stock yards at Chicago cover 50o ac. and 13,00o enclosures. Chutes and runways are provided for the unloading of the live stock into pens. The Federal law passed in 1906 provides that live stock must not be confined for longer than 28 consecutive hours without unloading for rest, water and feeding. Therefore pens must be maintained en route at inter mediate yards for accommodation of the cattle on long runs. In addition to the pens and corrals, facilities for watering and feed ing, including storage tanks, troughs and hose connections, are maintained.