When the ice tanks are placed at the ends of the car gravity will not maintain a circulation of air. As the ice melts, the upper strata of air remains warm. To avoid this feature, resource is had in a forced draft. The air in the upper part of the car is collected by a fan and forced through tubes extending through the ice tanks and opening on to the floor of the car. In connection with the fan is an inlet and outlet tube, by which a gradual change of air is effected.
Ventilating Refrigerator Cars.—In some cars there is no provision for renewal of the air; the object is, no doubt, economy of ice, and for very low temperature, or for short trips, it is an advantage which does not have any ill effects on the contents of the car. For long trips and moderate temperatures, a change of air is beneficial, in most instances.
In some cars, ventilation is so arranged that the air can be changed or not, as desired. The fans are run by motion taken from one of the car axles, and are arranged to be run by hand when the car is not in motion.
Icing Refrigerator Cars.—When a train is to be loaded with beef or mutton, it is set in on a track alongside of the icing platform. By means of double tracks on either side, as many as fifty cars can be iced at short notice. Ice cakes are delivered on a staging above the platform by elevator, suited to the location, and run into the hopper of a large power ice breaker. Barrows, of a capacity of five hundred pounds of broken ice, are set below the breaker, and, by withdrawing the damper, are filled with ice. From two to four shovelfuls of salt are added, and the barrow is dumped into the mouth of a chute which runs along the edge of the platform, delivering the ice directly into the door above the ice tank. About four tons of ice are placed in each car. By an extension spout the cars are filled in the same manner on the farther tracks. After icing, the cars are loaded, and at intervals on their journey the ice is replenished.
In shipping other goods, which are not wanted below the freezing point, ice is used without salt. Even with such goods, the more frequent use of ice would often be advisable.
Value of Ice in Transportation.—It is difficult to imagine the state of affairs which would ensue upon a withdrawal of all refrigerator service upon our railways. The amount of privation and actual suffering which would follow would be felt directly in every community in the land. To most people the blessings which follow in the wake of the refrigerator car are of a kind which are accepted without question, as a matter of course. It would be a long list, to enumerate all the advantages which are now mutually divided between the producer and the consumer of the products of our farms, gardens, vineyards, dairies and fisheries, dependent, in whole or in part, upon this service.
It is but a short time since hundreds of bushels of fruit were left to decay on the ground in California orchards, while many other sections were destitute of fruit. Now a refrigerator car service delivers these fruits at all the Atlantic coast cities, as well as points between. Trial shipments have been despatched to London, with gratifying results, and it is more than probable that large quantities of the products of these famous orchards will delight our cousins across the sea.
Refrigerator Vessels.—On board the fastest steamships plying between our Atlantic ports and Europe, are found extensive refrigerator compartments. Dressed beef and mutton are exported in large quantities, as well as fruits, vegetables, dairy products and oysters. The temperature, for meat, is maintained a few degrees below the freezing point. Air machines are principally used on the ocean, the brisk circulation of air which they maintain being an advantage. The enormous quantities of dressed meat transported from the United States, Argentine, New Zealand and Australia, to Europe, requires a large fleet of steamers, some of which are equipped, at considerable expense, for this special service. In connection with these vessels, at both shipping and receiving wharfs, are large storehouses, where the frozen meat is held, awaiting shipment, or received after its voyage.
In Transporting Fruit on the Ocean, a large fleet find employment; in it are found steamers built with insulated hulls formed by lining the outer steel hull with wood and packing the inclosed space with powdered charcoal. Refrigerator service is essential to success in transporting the more delicate fruits such as pears, peaches, cherries and plums which have been landed in London from California and South Africa in excellent condition in this way.
Ventilation, in connection with insulated hulls, is depended on in handling most of the tropical fruits imported into this country. Bananas from Central and South American and West India ports form the staple commodity, giving employment to an extensive fleet of very excellent boats. From Southern Europe large quantities of fruit are exported, oranges, lemons, grapes and nuts forming the bulk of the shipments which are carried in steamers in well ventilated compartments.