The cars on a freight train are seldom all alike; they are usually of many sizes and perhaps many colors, and there are different kinds of cars for different kinds of freight. The cars used on the first railroads were very much like the stagecoaches and wagons used on ordinary highways. The early railroad was merely a new kind of highway, and to make cars for it the railroad builders put flanged wheels upon the vehicles with which they were already acquainted. After the invention of the steam locomotive, which could pull "trains" of cars, railroad managers found it possible to use larger and heavier cars, both for passengers and freight, and it was not long until the railroad cars became wholly unlike the stagecoaches and wagons after which the early cars had been copied.
The steam railroad was not very old when railroad managers began to use several different kinds of freight cars. Coal could be carried in open cars, because rain and snow would not injure it, but grain and flour, drygoods and groceries, and many other articles had to be carried in closed cars which would protect their loads from the weather and from the flying sparks of the locomotive. For the transportation of logs and lumber still another kind of car could be used, and a special kind of car was built to haul cattle and hogs and other live stock. As time went on and railroads carried more and more freight, bigger and better cars were invented for hauling different kinds of freight.
Today our railroads have several classes or types of freight cars, and there are a number of different kinds of cars in each class.
The simplest type of car is the flat car. It is merely a platform car with neither sides nor ends above the floor. It is used to carry logs, lumber, stone, steel rails and beams, and heavy pieces of machinery. Sometimes you may see a train hauling steel bridge beams or wooden poles so long that they need several flat cars together to carry them. Along the sides and at the ends of the floor of the flat car there are usually a number of metal pockets, in which wooden stakes may be placed, if necessary, to hold freight on the car. If you have ever seen a flat car loaded with lumber perhaps you have noticed how the lumber is held in places by these stakes. The type of car that is used to carry coal is familiar to everybody. Similar cars are used to haul ore, gravel, crushed rock, cinders and other loose bulky materials which wet weather will not injure. Because such cars have sides and ends above the floor, but no roof, they are sometimes called "opentop cars."
There are two common types of open-top cars, the gondola car and the hopper car. The chief difference between these two is that the gondola car has a flat floor or bottom, while the hopper car has a floor which slopes downward from each end, and in some cars from the sides also. The bottom of the car has two or more hoppers, with doors that open downward. When these doors are open the entire contents of the hopper car will drop out. A few gondola cars are made with hopper bottoms. That is, the floor of the car has one or more hoppers to be used in unloading the car. The entire contents of the car will not drop out, however, when the hopper doors are opened, because the floor of the car does not slope toward the hopper, and some of the load will be left on the level part of the floor. This part of the load must be pushed through the hopper opening with shovels.
Some gondola cars are made with drop bottoms. Nearly the entire floor of a drop-bottom gondola consists of doors which open downward. Usually the doors run lengthwise of the car. and are arranged in pairs In some cars the hinges of the doors are at the center, and when they are opened the coal or ore with which the cars are loaded runs out at each side. In others the hinges are at the sides, and the doors
open at the center, letting the load fall directly beneath the cars. Other gondola cars are built with no doors in the floor at all. For shipments of rails and other steel mill products an unusually long car, often 65 feet, and known as a "mill type" gondola, is employed. Some are built with drop-ends so that they may be loaded with logs or poles or beams that are longer than the car.
The amount of freight which a gondola car can hold depends upon the size of the floor space and the height of the sides and ends. The gondola cars which are built especially for coke have very high sides. Since coke is lighter than coal or iron ore, it is desirable to use roomier cars for its transportation . Gondola cars, used chiefly for carrying coal or ore, may be fitted with racks when used to haul coke. These racks extend above the sides of the car, just like the extra "sideboards " of a farmer's wagon, and make it possible for the car to carry a much bulkier load.
An interesting specialized car is the well car, found in many steel plants, and used in transporting ingot molds. Well cars have been built with a load capacity of more than 250 tons. They are used for hauling machinery. The most common type of car is the box car, the car which is used to haul grain, groceries, drygoods, furniture, hardware, automobiles and all kinds of ordinary merchandise.
The body of the car is merely a huge box, with a sliding door on each side. The roof slopes gently toward each side, and in the center of the roof, extending from one end of the car to the other, is a narrow "running-board," over which the trainmen may walk or run. Have you ever seen a brakeman walking on top of a train, stepping from one box car to another, and clambering over the loads on the gondola cars? Box cars are made in many different sizes. Very large ones are used for automobiles and furniture. Automobile cars have double doors or extra large single doors on the sides, and some of them have large doors at the ends, through which the automobiles can be loaded and unloaded.
Box cars that carry grain in bulk must be fitted with "grain doors" in addition to the ordinary doors. These grain doors are set across the lower half of the door opening, and they keep the grain from leaking out, when the car door is pushed back. Box cars built specially for hauling grain have grain doors, which, when not in use, can be suspended from the inside of the roof. When the ordinary box cars are used for grain, the grain doors are nailed in place at the elevators where the grain is loaded, and they are taken out when the grain is removed from the cars.
Many box cars in which automobiles are carried are provided with a specially designed steel framework to permit the loading of automobiles one above another, virtually doubling the capacity of the car. Many railroads use movable bulkheads in their box cars to hold less-than-carload freight securely in place. The boxes, barrels and other containers in which lessthan -carload freight is shipped are likely to vary widely in size and shape. Moreover, shipments destined for several difference places are often loaded in the same car. The problem of stowage becomes a difficult one, and if some precaution is not taken to keep packages from shifting, many of them are likely to be damaged. By the use of bulkheads, firmly fastened to side walls, a car can be divided, as it were, into compartments of whatever size or number desired, and freight for a single station can be packed tightly in a single compartment, and packages different in size and shape can be loaded so securely that there is little risk of damage if the car is handled roughly during its journey. The refrigerator car is a special kind of box car, used for hauling fresh meats, fruits, vegetables, fish, milk, and other articles which must be kept cold to prevent their spoiling. Most refrigerator cars depend upon ice or upon a mixture
of ice and salt to keep their contents cool; but some have a cooling system made up of tanks and pipes for the circulation of cold brine. The walls, floor and roof of a refrigerator car are waterproof and airtight, and they are "insulated," to keep out the heat of the air. They are made of several layers of material. The inside layer is of wood, and the outside layer is usually of wood, though sometimes there is an outer layer of metal. Between the inner and outer layers is the insulating material, one or more layers of hairfelt, corkboard, kapok, or other substance, through which heat will not pass readily. Sometimes air spaces are left in the walls, for "dead air" gives excellent insulation. The layers of insulating ma
terial are covered with one or more layers of waterproof paper or fabric. Neither water nor air can enter the walls, roof or floor of a well built refrigerator car. The doors of the car are also insulated; they are swinging instead of sliding doors and arc made so that they may be tightly closed. Most refrigerator cars have ice bunkers or baskets at each end, but in some the ice bunkers are just beneath the roof in the middle of the car. Ice and salt are put into the bunkers through hatches in the roof.
Refrigerator cars have wooden, steel or aluminum bulkheads , partitions at the ends which extend not quite all the way from floor to ceiling, just between the ice bunkers and the space in which the freight is carried. A bulkhead keeps that part of the load nearest the ice from getting too cold, and it also helps to make the air circulate inside the car. It is only by the circulation of the air that the load of the car can be chilled. You probably know that the warm air in a room rises, while the cold air falls. The air about the ice bunker in a refrigerator car becomes cold and falls, flowing under the bulkhead along the floor of the car, giving off its chill to the freight. As it becomes warmer it rises toward the roof and Hows back over the top of the bulkhead, where it again becomes chilled and falls to the floor.
The most up-to-date refrigerator cars have forced circulation of air created by fans placed at each end of the car, near the floor and adjoining the bulkhead on the side opposite the ice bunker. These fans are run by a belt extending from a wheel on the fan shaft, which protrudes from the bedy of the car, to another wheel of rubber, which is held by springs against the tread of one of the car wheels. When the car is in motion the fans are made to rotate, their speed depending of course upon the speed at which the train is moving. In a car equipped with fans the course of the circulation of the air is just the opposite of the natural course of circulation described above The air is forced upward through the ice bunker and flows toward the middle of the car, falls toward the floor, and flows back toward the fans. The forced circulation of air creates a more even temperature in all parts of the car.
The newest refrigerator cars have yet another improvement. They are convertible, that is, their ice bunkers are collapsible,
and their bulkheads can be folded back against the sides of the car or upward to the ceiling. Refrigerator cars often carry freight which requires no refrigeration. If the bulkheads and ice bunkers are fixed, some twelve per cent of what might otherwise be loading space is lost. The convertible car has a considerably greater capacity for freight that needs no cooling. In recent years American railroads have begun to make use of dry ice as a refrigerant. Dry ice is the gas, carbon dioxide , reduced to a solid state. It has a temperature of more than 100° below zero. It is frequently used alone as a refrigerant either in individual containers of ice cream or poultry, or in refrigerator cars. The most common method of using dry ice in refrigerator cars is to combine it with water or wet ice. Refrigerating engineers claim that a combination of dry ice and wet ice provides a more satisfactory refrigerant for the shipment of perishable commodities, and also reduces the cost of transporting such commodities in freight trains. Dry ice is now used quite commonly instead of a mixture of wet ice and salt, when it is desired to ship perishable articles in a frozen condition.
There is no special type of car more interesting than the refrigerator car. Before it was invented, more than 75 years ago, it was impossible to ship fresh meats and fresh ripe fruits for long distances. The cattle and hogs, which furnished fresh beef and pork for the people of large cities, had to be shipped to the cities for slaughtering. People living in small towns, which had no local slaughter-houses did not have fresh meat very often, but had salted meat nearly the entire year round. The refrigerator car made a very great change in the fresh meat business. It made it possible for great central meatpacking plants to supply the wants of millions of people for fresh meat. Though there are still many local slaughter-houses throughout the country, a very large part of the fresh meat sold in the butcher shops of the Eastern, Central and Southern States comes from the great packing houses of Chicago, St. Louis, Omaha, and other cities in the corn belt, where so many cattle and hogs are fattened for the market. Every day whole train loads of fresh meat are sent from these packing plants to the large cities of the East. The packing houses also send out large numbers of "peddler cars"—refrigerator cars loaded with all kinds of fresh meat—which is delivered in local freight trains to small villages and towns.
What the refrigerator car has done for the fruit business of the United States is just as interesting and important as what it has done for the meat business. It is the refrigerator car which makes it possible for people in the eastern part of the United States to have on their tables all the year round the oranges which grow in the orchards of sunny Florida and California. It is the refrigerator car which distributes the wonderful peach crops of Georgia and Michigan. Bananas come from Central America to New Orleans, New York and other ports, and are carried all over the country in refrigerator cars. Watermelons, cantaloupes, grapes, strawberries and raspberries , and all kinds of fresh, green vegetables are shipped hundred of miles from places where they have grown. The refrigerator car makes it possible for all of us to have greater variety of good, wholesome food.
Recent years have found many engineers at work endeavoring to improve refrigerator cars. Some of the improvements have been mentioned. One reason why it has been necessary to improve these cars has been the introduction and the greatly increased consumption of frozen foods in America. There is hardly a grocery store in the country today that does not sell a wide variety of frozen fruits, vegetables, fish and meat. Most of the frozen foods bought at these stores are prepared in large freezing plants and may be shipped hundreds of miles by train and truck before they reach the stores where they are sold. The distribution of frozen foods has greatly enlarged the demand for more and better transportation under refrigeration.
Refrigerator cars are used to carry fruit and vegetables in the winter, as well as in the summer, though one could hardly say they were being used as "refrigerator" cars in the winter time. The insulation, which keeps out the heat on warm days, keeps out the cold in the winter, and if the distance is not too great, fruits and vegetables can be carried in refrigerator cars, during fairly cold weather, without danger of freezing . When it gets very cold, however, even refrigerator cars, with their thick, insulated walls, do not give enough protection to potatoes and apples and other vegetables and fruits. So the railroads must have heated cars for use in those parts of the country where the winters are likely to be very cold. Some refrigerator cars have small charcoal, alcohol, or oil stoves, so that they can be used as heater cars, when necessary. The stove is beneath the door of the car, and the air which it heats is carried inside by a pipe or flue. Box cars are often turned into heater cars just by placing small kerosense or coal stoves in them, the stovepipes extending through holes cut in the sides of the cars. Some heater cars are fitted with steam pipes along the floor and are warmed with steam from the locomotive boiler.
Many fruits and vegetables can be shipped without eithei heating or refrigeration, at least during certain parts of the year, but to keep from spoiling, they need much more air than they can get in the ordinary box car. Because of this, railroads have ventilator cars, which are merely box cars with screened openings at the ends, and in the doors. These openings permit fresh air to move freely through the cars when the train is in motion. Some ventilator cars are insulated, just like refrigerator cars, to keep out the heat of the sun, and some of them have fans to provide a forced circulation of air. It is a frequent practice on the part of shippers of fresh, crisp vegetables, such as spinach, lettuce and carrots, to cover the boxes of vegetables with crushed ice after they have been loaded in a car. The ice may be finely crushed and blown into the car by an ice-spraying machine, operated by compressed air, or it may simply be thrown over the boxes by a shovel in ihe hands of a brawny workman. As the crushed ice melts the cold water drips and trickles down on the vegetables, keeping them in crisp and fresh condition until they arrive at their destination. In many vegetable stores you will see counters where vegetables are kept in fresh condition by the same method.
Refrigerator cars are often pre-cooled before starting on their journey with a load of fresh fruit or vegetables. At many of the orange warehouses in California, after the boxes of fruit are loaded, a mechanical refrigerating machine draws off the warm air of a car and blows in cold air. The operation may be repeated until the car and its contents are properly chilled, after which the ice bunkers in the car are filled, the doors tightly closed, and the car sent on its way. Pre-cooling means that the fruit is in good condition when it leaves the warehouse, and it means too that the refrigerator car will not have to be re-iced so often during a long cross-country journey. Where special pre-cooling facilities are not available, refrigerator cars equipped with fans, as previously described, may use these fans for pre-cooling their lading. Small portable electric motors operate the fans, with the same effect on the circulation of air within the car that would be obtained if the car were traveling at a speed of fifty miles an hour.
Most of our refrigerator cars are owned by the railroads, either directly or through a subsidiary company, but not a few shippers have found it advisable to have cars of their own, in order to be assured of a full supply in time of need. When you are watching a train of refrigerator cars pass by you will often notice the trade mark or the name of some meat packing or milk company on the sides of some of the cars. There are a few independent car companies that are neither shippers nor carriers, which build and own refrigerator cars and other cars of a special kind. These companies lease or rent their cars both to railroads and to shippers. Many tank cars are privately owned and leased to shippers who have need for them. The same used to be true of coal cars, but nearly all of these are now owned by the railroads. In Great Britain the ownership of freight carrying cars by the shippers is much more common than in the United States.
The stock cars, in which railroads transport horses, cattle, hogs, sheep and other live animals, have roofs, but the sides are slatted, to give plenty of light and air. Stock cars which carry hogs and sheep are usually built with double decks, that is, they have an extra floor halfway between the roof and the bottom floor of the car. Double-decked cars can carry twice as many animals as cars with single floors. Stock cars used in transporting chickens and ducks and other kinds of poultry are covered with wire netting. They are fitted with several rows of shelves, upon which the crates of poultry are placed.
Stock cars are much more common in the central and western parts of the United States than in the eastern, for it is in those sections that most of the live stock of the country is raised, and it is there that the large meat-packing plants are located.
Very often a stock car which carries a load of hogs or canle from a stock raising district to a large meat packing center returns with a load of coke or lumber or some other article which ordinarily is shipped in open-top cars. A railroad manager is always glad to get a "return load" for a car. It does not cost much more to haul a loaded car than an empty one, and it is only the loaded car which earns money for the railroad.
Liquid freight, such as oil, acid, molasses, wine, milk, or mineral water, may be transported in tank cars. A great deal of liquid freight is carried in wooden or steel barrels or drums, or in glass carboys, but when large shipments are made, tank cars are more economical. The tanks are built of steel. At the top of a tank is a dome, with an opening through which the tank is filled and emptied. There is also a valve at the bottom of the tank, through which the liquid contents of the tank may be drawn off. Some liquids form gas if they become too warm, and tank cars have safety valves, similar to the safety valve on a steam locomotive, which open and permit the gas to escape when the pressure reaches a certain point. Some of the tank cars which carry acids are lined with lead, or rubber, because some acids will eat through steel but will not injure lead or rubber. Tank cars which carry mineral water or milk or other liquids which must be kept perfectly clean, are lined with glass. Tank cars which carry milk are also insulated. Another type of car is the container car. It is a fiat car, carrying several removable containers or boxes which may be lifted from the car and set upon a dray or a motor truck. Goods are packed into a container at a factory or warehouse, the container is carried by truck to the car, hauled by rail.
and taken by truck to the final destination. The container car reduces the work of loading and unloading cars at freight stations and lessens the danger of loss and breakage of the goods which they carry. When container cars were first introduced it was thought that they would be used solely for the transportation of valuable merchandise, usually shipped in less-than-carload quantities , but it has been found that container cars are also useful for carrying various kinds of low grade freight. Many bricks
are shipped in container cars, and container cars are used also for the transportation of cement. Some container cars are built, the containers of which are simply demountable tanks used in the transportation of milk and cream.
The car which you see at the end of a freight train is not a freight car of course, but it is at least a freight-train car. We usually call it the "caboose," but it is also know as a "cabin," or "train car" or "conductor's car." In this car the conductor and brakemen ride between stations. The conductor also uses this car for his office, in which he keeps his papers and prepares the records which he must make out, telling of the day's business of his train. It contains the flags, lanterns and tools needed on the train. At each end of the caboose is a platform and door; inside are lockers or cupboards, and comfortable seats and bunks. At the top of the caboose is a cupola, with windows front and rear, through which the conductor and brakemen can keep a sharp lookout in both directions. A little coal stove keeps the caboose warm and cozy in cold weather. Some of the latest cabooses, instead of having cupolas, have a bay window in the middle on each side, each window fitted with a small table and a reversible chair.
The important parts of any freight car are the body and the trucks. The body is the part which carries the load of freight. The trucks are the wheels and the frame about them, upon which the body of the car rests. Each freight car has two trucks. A truck has either four or six wheels.
The bodies of the first freight cars were built almost altogether of wood. Freight cars of today are made largely of steel. Nearly all open-top cars now built have bodies made wholly of steel; many box car bodies are also made entirely of steel, and a great deal of steel is used in building our "wooden" cars. You do not often see a freight car with a wooden roof. Many box cars which have wooden sides have steel ends, and very often the framework of the bodies of wooden stock cars is made of steel. And in nearly all cars the underframe—the frame just beneath the floor—consists entirely of steel. Steel has taken the place of wood in freight cars for many reasons. The chief reason is that steel is so much stronger than wood. Railroad managers want large cars which will carry heavy loads, because large cars reduce the cost of transportation . This is true because a large car will carry much more for its weight than a small car. That is, two cars, each of which will hold fifty tons of freight, will weigh much more than one car which will hold one hundred tons. It would not be possible to make a car of wood which would be strong enough to bear the heavy loads which are put into our steel freight cars.
Another reason why steel is used in place of wood is that steel stands jars and bumps better than wood. A freight car
gets bumped around a great deal during its journeys about the country. Bumps and jolts which will cause wood to split and splinter will only cause steel to bend and twist. A steel car which has been jolted about can be repaired more easily and more cheaply than a wooden car that has been roughly used.
Still another reason why steel is better than wood is that steel will not burn. It often happens, when a freight train is wrecked, that wooden cars catch fire, burning up both cars and freight.
Some people think that steel cars are better than wooden cars because steel "lasts longer" than wood. But this is not always true. If a steel car is not painted regularly, it is likely to wear out from rust more quickly than an unpainted wooden car will rot away. The life of a freight car, whether made of steel or of wood, depends much upon how well it is cared for.
Steel has one great drawback as a material for the construction of freight cars. It is heavy. In these days of the airplane and the motor vehicle the demand for more speedy movement of persons and goods can be heard almost daily. For several years railroads have been using lighter materials in the manufacture of the passenger cars in their fast trains, and now they are turning seriously to the problems of making freight cars of lighter weight. Many aluminum tank cars have been built. Late in 1944 the Great Northern Railroad made in its own shops the first American box car with a body composed largely of aluminum. The body was lined with light plywood, but the exterior was made entirely of aluminum-alloy sheets. Of fifty tons capacity, this car weighed 43,500 pounds, or 4,000 less than a steel car of equal capacity.
In 1945 the Mt. Vernon Car Manufacturing Company turned out three box cars the entire bodies of which, as well as parts of what we might call the chassis, were made of aluminum . The underframes, trucks, couplers, bolsters, and air brake equipment of these cars were of steel, but even in the construction of some of these parts a saving in weight was effected by the use of low-alloy steel of greater strength but of less weight than the conventional carbon steel. Two of these cars were designed for use in passenger trains, as well as in freight trains, and consequently were equipped with steam and air signal lines as well as with an air brake line. An interesting feature of these cars, and also of the Great Northern car, was the use of reflective materials, either on the car body or on the journal box lids, which would serve to warn reckless automobile drivers who might try to cross a railroad track already occupied by a train.
Already the performance of these light weight cars has justified their construction, and many cars, of all types, with bodies of aluminum, stainless steel, or other material lighter than ordinary steel, have been built or have been ordered from car builders. Other methods of making freight cars lighter are being tried. Just as in shipbuilding, the welder is taking the place of the riveter. Many of the new materials which have been developed during the war years will doubtless find iheir way into the manufacture of railroad equipment. The search for improvement never lets up.
If you look closely, you will find lettering on the side of a freight car. Of course you have noticed that the cars have numbers and that they have the names of the railroads to which they belong. But have you noticed that a car tells the month and year in which it was built; and that it shows how heavy a load it can carry? A box car tells how long, how wide and how high it is. Nearly all cars have information printed on their sides about the kind of air brakes and couplers they have. This information is useful when a car has to be repaired away from its home road.
Freight car trucks, unlike freight car bodies, were never made entirely of wood, but it was not so very long ago that nearly all of them were made partly of wood. You would look a long time now to find a car truck not made wholly of metal.
Car wheels are made of steel or of very hard cast iron. Unlike the wheels of a wagon or carriage, which turn upon their axles, the wheels of railroad cars are fastened tightly upon their axles, and the axles turn as the wheels turn. The ends of an axle extend out a few inches from the wheels. These extended parts of the axles carry the weight of the car. They are called "journals." Surrounding a journal is a "journal box." Maybe you have looked into a journal box and seen the "waste" and oil in the bottom. It is very important for the journal to have plenty of oil. If not, it becomes so hot that it causes the waste to smoke and even burst into flame. When this happens we say the car has a "hot box."
In the upper part of the journal box, resting directly on the journal, is the "journal bearing" or "brass." It is upon
this bearing that the weight of the car rests. It is the friction between this bearing and the journal which causes a hot box, unless there is plenty of oil.
Extending from one journal to another, and resting on the journal bearing, is the "side frame" of the truck. If the truck has only four wheels, this side frame is usually a single heavy steel frame. In the center of the frame you see some heavy springs, and supported by these springs is the "truck bolster," which stretches across beneath the car from one side frame to the other. Just above the truck bolster, and connected with it in the center by a thick steel pin or bolt, is the "body bolster" of the car. The long steel floor center sills of the car rests upon two body bolsters, and through them upon the two car trucks.
Since the body bolster and the truck bolster are connected by a pin or bolt, the car truck may turn beneath the car. When you are watching a train move slowly around a curve it is easy to see the trucks turn. You can see the moving of a car truck even better when a street car turns a corner. Six-wheel trucks are used under freight cars which are made to carry very heavy loads. The side frames of these trucks are sometimes in two parts, and there are two truck bolsters, one on each side of the middle pair of wheels. Cross beams connect the two truck bolsters, and make a bearing upon which rests the body bolster of the car.
Each wheel of a car has a cast iron, steel-backed brake shoe which presses against the wheel when the engineer "puts on the brakes" to slow down the train or bring it to a stop. The brake shoes are carried by brake beams, and these beams are connected by a system of rods and levers with the piston in the air brake cylinder of the car. The brake rods, levers and beams are supported by hangers fastened to the underframe of the car or to the truck bolsters. The brake gear on each car also has a connection with a brake wheel, on the top or at the end of the car. A brakeman may set the brakes of the car by hand, when necessary, by turning the brake wheel.
One of the most interesting parts of a car is the coupler. Have you ever noticed how the cars of a train are joined together? You can understand how car couplers work if you will curve the fingers on both hands and hook your hands together. Keep your fingers bent and pull. How tightly your hands hold to one another. Keep on pulling and straighten the fingers on either hand or on both hands. What happens? The part of the coupler which acts as a hook, just as your curved fingers, is called the "knuckle." When two cars are coupled together the knuckles are locked tightly in place and the cars can not come apart. To uncouple them a brakeman works an iron lever extending from the coupler to the side of the car. This lever operates the coupler lock and permits the knuckle to swing out, and one car can be drawn away from the other.
The best thing about car couplers is that they are "automatic ." That is, when two cars meet, with knuckles turned out, the pressure of one coupler against the other causes the knuckles to close and the locks to fall in place. Before the days of automatic couplers, cars were joined together by "link and pin" couplers. A heavy iron link extended from a drawbar on one car to a drawbar on another,
and a movable iron pin, passing through the drawbar and link on each car, held the cars together. The cars could be neither coupled nor uncoupled without a brakeman stepping between them, to handle the links and pins. Such couplers caused many accidents, brakemen having their hands crushed between the drawbars, or slipping and falling beneath the wheels of the cars. After the automatic coupler was invented, laws were passed forbidding railroads to use link-and-pin couplers. The automatic coupler is one of the finest "safety devices" ever invented.
Though our railroad freight cars have several varieties of automatic couplers, the coupler knuckles and some of the other parts all have the same shape, to enable any two cars to be coupled together. It is also necessary for all car couplers to be placed at about the same height above the railroad rails. This standardization has been required by law.
Car couplers are not fastened rigidly to the frames of cars. If they were, the shock of starting and stopping a train would cause the couplers to break and the cars to be badly damaged. The couplers must have some "give" or "play" in them. This "give" is furnished by a "draft gear." The first draft gears had springs to take up the shocks caused by starting and . stopping trains. All modern heavy freight cars have "friction draft gears," in which the force of the shocks is taken up by the friction of metal plates and wedges rubbing against one another.
The draft gear is held between two sills beneath the floor of the car near the end. Around the draft gear is a steel strap called a "yoke." The ends of the yoke are fastened to the coupler with a large steel key. If you look closely at the coupler of a freight car you can see the key which holds yoke and coupler together. When a train starts the couplers move out a little from the cars. They look just as if they were stretching. This means that the pull of the locomotive is applied gradually to the body of the car, the "give" of the draft gear taking up most of the shock and keeping cars and couplers from being damaged. On some box cars the draft gears are cushioned with rubber. Railroads take nearly as much care for the safety and comfort of their freight as for the safety and comfort of their passengers, and thereby steadily reduce the amount of shippers' damage claims.