Education Part 7
Un-Powered Railroad Cars
Introduction
Unpowered railroad cars constitute the bulk of railroad traffic and enable railroads to transport large quantities of goods and passengers between source and destination. There are two broad classes of unpowered railroad cars, freight and passenger (and some hybrids).
Source of Revenue
Passenger and freight cars (also known as carriages and wagons in many parts of the world) constitute the principal source of revenue for railroads. Today, in the United States, most railroad revenue is derived from freight transport. This can be seen in the following graphic, which displays freight revenue for North American Class I carriers (see Classification of Railroads in What is a Railroad?).
Introduction
Unpowered railroad cars constitute the bulk of railroad traffic and enable railroads to transport large quantities of goods and passengers between source and destination. There are two broad classes of unpowered railroad cars, freight and passenger (and some hybrids).
Source of Revenue
Passenger and freight cars (also known as carriages and wagons in many parts of the world) constitute the principal source of revenue for railroads. Today, in the United States, most railroad revenue is derived from freight transport. This can be seen in the following graphic, which displays freight revenue for North American Class I carriers (see Classification of Railroads in What is a Railroad?).
Operating revenue of the seven Class I North American railroads in 2021 (in billion U.S. dollars)
However, in other parts of the world, most notably Europe, Japan and China, significant revenue is derived from passenger transport. These are the areas in which truly fast trains operate. The graphic below shows passenger revenue (in Euros per train-kilometer) in 2019 for 14 European countries. An Euro (€) per train-kilometer is the revenue derived as a passenger train travels 1 km (0.621 mi). For France, assuming a trip of 500 km (311 mi), revenue amounted to €19,070 ($20,024). Total passenger train-kilometers for France in 2019 was 112,614,000, thus total revenue was €4,295,097,960 ($4,510,000,000).
Passenger revenue in Euros per train-kilometer for 14 European countries
Contrast this with the passenger revenue for Amtrak for 2019 of $3,503,520,000. The population of France is about 20% that of the United States.
Types of Unpowered Railroad Cars
There are two broad classes of unpowered railroad cars: passenger and freight (carriages or wagons). Obviously the things transported are people or goods.
Passenger Cars (Carriages)
Passenger cars of several types have been employed as determined by the purpose of the particular train under consideration. Passenger car types include coach, sleeping, dining, entertainment, observation, lounge and hybrid cars.
The most common type of passenger car is the coach or chair car. Such cars often have two rows of seats with a center aisle. The seats may be individual (often reclining), but are sometimes bench seats, depending on the quality of service on offer. These are called open coach cars (see below).
Types of Unpowered Railroad Cars
There are two broad classes of unpowered railroad cars: passenger and freight (carriages or wagons). Obviously the things transported are people or goods.
Passenger Cars (Carriages)
Passenger cars of several types have been employed as determined by the purpose of the particular train under consideration. Passenger car types include coach, sleeping, dining, entertainment, observation, lounge and hybrid cars.
The most common type of passenger car is the coach or chair car. Such cars often have two rows of seats with a center aisle. The seats may be individual (often reclining), but are sometimes bench seats, depending on the quality of service on offer. These are called open coach cars (see below).
An open-type [3+3] coach or chair car of Indian Railways, India
Coach cars may also be double-decked, particularly on commuter trains where it is more important to move large numbers of people quickly than to be concerned with comfort. In such cases, the distance traveled is usually short. On the other hand, double-decked cars may be designed so that the upper deck is for observation. These are sometimes called "dome cars" and are used on routes that enable passengers to enjoy the scenery as they pass. In some examples of this type of car, a portion of the upper deck (sometimes lower deck) is open to nature, thus facilitating unobstructed photography and viewing.
Coach cars may also be of the closed type. These are also called compartment cars. Two seats face each other within a glassed enclosure. Each seat usually accommodates two or three passengers, with luggage storage overhead. An aisle (also called vestibule) is usually along one side of the car, with entrance to the aisle at either end of the car. However, some cars of this type have multiple entrances to the aisle from outside (from a platform).
Compartments may differ according to the class of service on offer, with some compartments designated coach class and some business or first class. Of course compartments also may be designated for smoking or non-smoking passengers. Coach cars also have toilet facilities, usually at one end of the car.
Sleeping cars are designed for the comfort of passengers on long-distance routes. Several kinds of sleeping car have been used. One kind has double-deck or "bunk" beds with shared bathroom facilities at one end of the car. The upper bed can be folded up during the day with the lower one converted to a bench-style coach seat. Limited privacy is provided by curtains.
Another kind of sleeping car is divided into compartments, sometimes with toilet and lavatory. Compartments are typically for two people sleeping bunk style and offering greater privacy. Shared shower(s) may be located at the end of the car.
Other sleeping car arrangements include the roomette for a single person and including full bathroom facilities. A drawing room car would offer sleeping accommodations for 3-4 persons with full bathroom facilities.
The image below shows an "open section" sleeping car (Budd Company called them Slumbercoaches) in which each section can be converted into "bunk" beds with privacy provided by a curtain.
Another kind of sleeping car is divided into compartments, sometimes with toilet and lavatory. Compartments are typically for two people sleeping bunk style and offering greater privacy. Shared shower(s) may be located at the end of the car.
Other sleeping car arrangements include the roomette for a single person and including full bathroom facilities. A drawing room car would offer sleeping accommodations for 3-4 persons with full bathroom facilities.
The image below shows an "open section" sleeping car (Budd Company called them Slumbercoaches) in which each section can be converted into "bunk" beds with privacy provided by a curtain.
An open section sleeping car in day-time orientation. Each section converts into a pair of bunk beds with privacy curtain (Pullman car circa 1950)
Dining cars may be designed in various ways, depending on passenger manifest, timing, class of service, kitchen design and other factors. Dining may be first-come, first-served or on a scheduled basis (e.g., 5, 7 and 9 p.m.) either assigned by sleeping car or by reservation. Dining cars may offer snacks, a fixed menu (table d'hôte), à la carte or multi-course service or some combination of these. Dining service also varies with the time available to offer the service. The following photo shows one style of dining car.
Example of a dining car as appeared on an Austrian inter-city train in 2008
Entertainment cars are rare, although in former times complete productions were sometimes offered. Card games and other similar activities are sometimes available in a lounge car or in coach cars equipped with tables.
Observation cars, when included in the consist, are of two or three types. One type is often the last car on a train and offers viewing through the windows of the car. A common type today is a two-deck car with the upper deck enclosed at sides and top in widows, allowing good viewing of the surrounding countryside. The lower deck may offer coach seating, dining or lounge services. Some observation cars have a portion of the upper (preferred) or lower deck open to nature. This permits passengers with cameras to capture photos unencumbered by windows or ceilings.
Upper deck of an Alaska Railroad observation/dining car; the rear of the car is an open-air portion for unencumbered viewing and photography
Lounge or bar cars are designed to provide both comfortable seating and the services of a bar. Snacks may also be offered. In some cases, a dining car may serve as a lounge car at other than meal times. More luxurious trains will probably have dedicated lounge cars. Individual railroad companies may configure cars for more than one purpose as passenger traffic and preference dictate. These may be called hybrid cars.
The consist of a passenger train, that is the complement of cars, powered and unpowered, that make up a train, will be determined by the railroad company based upon the route, the number of passengers continuing to the ultimate destination and other factors, balanced against cost vs. return for each train.
Passenger Car Manufacturers
At one time, many passenger-car manufacturers existed, but today there are relatively few. Pullman Company was once the premier builder of railroad cars.
Today, the following companies are among the leaders in railroad car manufacture:
Alstom, (many locations)
Bombardier Transportation (many locations)
Budd Company (No longer operating; Philadelphia, Pennsylvania)
CJSC Transmashholding (Moscow, Russia)
Construcciones y Auxiliar de Ferrocarriles, S.A. (Beasain, Spain)
Integral Coach Factory, Chennai, India
Kawasaki Heavy Industries (Kobe, Japan)
US Railcar Company (Columbus, Ohio)
For an extensive list of railroad car manufactures, go here.
At one time, many passenger-car manufacturers existed, but today there are relatively few. Pullman Company was once the premier builder of railroad cars.
Today, the following companies are among the leaders in railroad car manufacture:
Alstom, (many locations)
Bombardier Transportation (many locations)
Budd Company (No longer operating; Philadelphia, Pennsylvania)
CJSC Transmashholding (Moscow, Russia)
Construcciones y Auxiliar de Ferrocarriles, S.A. (Beasain, Spain)
Integral Coach Factory, Chennai, India
Kawasaki Heavy Industries (Kobe, Japan)
US Railcar Company (Columbus, Ohio)
For an extensive list of railroad car manufactures, go here.
Famous Trains
There are many trains that have achieved enduring fame for one reason or another. Most are passenger trains, since it is people who bestow fame. Here is a list of some of those famous trains.
In addition to these twelve trains, other trains have gained fame for different reasons. See "10 Trains that Changed the World" and "Top 10 Trains".
There are many trains that have achieved enduring fame for one reason or another. Most are passenger trains, since it is people who bestow fame. Here is a list of some of those famous trains.
- The Orient_Express 1883. This famous train, introduced by the Belgian Compagnie Internationale des Wagons-Lits (CIWL), operated from Paris to Istanbul (a distance of some 2738 km (1,700 mi)). This was not a fast train (even by the standards of the time), but it was intended to permit people to travel in comfort and safety. Many versions of this famous train have operated in the years since its inception, with service ending about 2006. It is still possible to travel by train from Paris to Istanbul, but at least four separate trains are now required.
- The Trans-Siberian Railway (construction 1891-1916). This is the third longest train route in the world, operating from Moscow to Vladivostok, Russia, a distance of some 9,289 km (5,772 mi). The trip takes about 8 days (averaging about 30 miles/hour). It is not a luxury train, but the scenery is worth the trip.
- The Flying Scotsman 1928. The locomotive started life as an A1 class numbered 1472, later updated to A3 class numbered 4472. The locomotive is the famous part of this train, operating from London, England to Edinburg, Scotland (about 400 miles (644 km), 8.5 hours). It was the fastest steam locomotive in regular operation and it is still operational at the National Railway Museum, York, England.
- Frontier Mail 1928. Frontier Mail operated between 1928 and 1996, transporting passengers arriving by ship from Europe directly from Ballard Pier in Bombay (Mumbai) to the city of Peshawar, Pakistan (now to Amritsar Junction), a distance of 1,893 km (1,176 mi), taking about 32 hours.
- The Grand Trunk Express 1929.This is a train on Indian Railways, running between New Delhi and Chennai, India (2,206 km (1,370 mi)).
- The Mallard 1938. London and North Eastern Railway (LNER) Class A4 4468 Mallard is a 4-6-2 ("Pacific") steam locomotive built in 1938 at Doncaster Works to operate between London, England and Edinburgh, Scotland. It had a streamlined design that enabled it to pull long-distance passenger trains at higher speeds than other locomotives. On July 3,1938,Mallard broke the world speed record for steam locomotives at 126 mph (203 km/h), a record that still stands.
- The Qinghai-Tibet Railway 1984-2006. This is a high-elevation railway (much of the line is between 13,000 (3962 m) and 16,000 feet (4877 m) above MSL) that connects Xining, Qinghai Province, to Lhasa, Tibet Autonomous Region of China (1,956 km (1,215 mi)).
- The Super Chief 1937. The Super Chief (Nos. 17 and 18) was the first diesel-electric powered cross-country passenger train in the United States, run by Atchison, Topeka and Santa Fe Railway. The Super Chief began scheduled service in May 1937 and ran 2,227 miles (3,584 km) from Los Angeles to Chicago over upgraded tracks in about 37 hours (about 60 mph or 97 km/h).
- The Shinkansen 1964. Designed and built by Japan Railway initially for fast travel between Tokyo, Nagoya and Osaka, Japan (515.4 km (320.3 mi)). This was the first high-speed line in Japan and it is the oldest high-speed line in the world. This train runs on purpose-built standard-gauge rail lines that support normal operation at velocities of up to 285 km/h (177 mph). Since inception, Shinkansen trains have carried billions of passengers.
- The Indian Pacific 1970. The Indian Pacific is a weekly passenger train service that runs between Sydney (Pacific Ocean), and Perth (Indian Ocean), Australia that earns it the reputation as one of the few truly transcontinental trains in the world. It first ran in 1970. The train offers motorail (auto car) service between Adelaide and Perth.
- Broadway Limited 1912-1995. This was a Pennsylvania Railroad flagship passenger train operating from New York City to Chicago, Illinois (907.7 miles (1,460.8 km)). The “Broadway” in the name referred to the broad way of the route, much of which consisted of four tracks. It was a competitor of the next train in this list.
- 20th Century Limited 1902-1967. The 20th Century Limited was an express passenger train on the New York Central Railroad (NYC). The train traveled between Grand Central Terminal in New York City and LaSalle Street Station in Chicago, Illinois, along the railroad's "Water Level Route" (south side of the Great Lakes). NYC inaugurated the 20th Century Limited as competition to the Pennsylvania Railroad, aimed at upper-class and business travellers. It made few station stops along the way and used track pans to take on water at speed. On June 15, 1938, streamlined train sets designed by Henry Dreyfuss were added to the route.
In addition to these twelve trains, other trains have gained fame for different reasons. See "10 Trains that Changed the World" and "Top 10 Trains".
Freight (Goods) Cars
In this section, we discuss and illustrate the various types of freight (goods) railroad cars in use today. We also describe the basic construction of these unpowered vehicles, since certain aspects are common to all rolling stock. For a detailed historical view of freight cars, see White, Jr., John H. The American Railroad Freight Car. Baltimore, MD: The Johns Hopkins University Press: 644 pp. Another useful reference is provided by CSX that gives both car types and dimensions.
Types of Freight (Goods) Cars
There are essentially six (6) types of freight car, each with several variants. These types and some variants are listed in the following table. For another useful source, click here.
In this section, we discuss and illustrate the various types of freight (goods) railroad cars in use today. We also describe the basic construction of these unpowered vehicles, since certain aspects are common to all rolling stock. For a detailed historical view of freight cars, see White, Jr., John H. The American Railroad Freight Car. Baltimore, MD: The Johns Hopkins University Press: 644 pp. Another useful reference is provided by CSX that gives both car types and dimensions.
Types of Freight (Goods) Cars
There are essentially six (6) types of freight car, each with several variants. These types and some variants are listed in the following table. For another useful source, click here.
Principal types of railroad freight cars and variants
Flatcars
The flatcar (flat, flat car) is one of the most adaptable and versatile railroad cars and there are several variants designed for specific purposes. Several of these are included in the table just above. Here is a photo of a plain flatcar. As can be seen, it consists of a steel frame riding on two 2-axel trucks. It has a wooden deck and you can see slots for stakes at the sides and ends. This example is from the Wiscasset, Waterville and Farmington (Maine) Railway which used a 2' (610 mm) rail guage. This railway ceased operation in 1936. Note that this example used truss rods under the center of the car for support rather than the steal beams of today.
The flatcar (flat, flat car) is one of the most adaptable and versatile railroad cars and there are several variants designed for specific purposes. Several of these are included in the table just above. Here is a photo of a plain flatcar. As can be seen, it consists of a steel frame riding on two 2-axel trucks. It has a wooden deck and you can see slots for stakes at the sides and ends. This example is from the Wiscasset, Waterville and Farmington (Maine) Railway which used a 2' (610 mm) rail guage. This railway ceased operation in 1936. Note that this example used truss rods under the center of the car for support rather than the steal beams of today.
Wiscasset, Waterville and Farmington Railway flatcar circa 1930 (narrow guage)
Staked flatcars used stakes (wood or metal) to prevent materials from falling off the sides. Bulkhead flatcars have end "walls" to prevent loads from sliding forward or backward on the bed. Intermodal flatcars are designed to carry highway semi-trailers or containers in order to compete but also cooperate with truck traffic on highways. Intermodal freight requires special loading and unloading facilities at ports, rail yards or shipper facilities. Centerbeam flatcars are designed to carry large bundled cargo such as lumber, drywall, plywood, and fence posts. A steel beam is constructed along the center axis of the car that permits secure binding of materials to the center beam. Such cars require loads to be balanced either side of the beam. Well flatcars are cars with the portion between the trucks depressed to accommodate loads with heights greater that would be allowed on a plain flatcar. Minimum clearance above the rails is 2.5 inches (63.5 mm). Double container cars are more similar to gondola cars without a solid bottom. Trucks (bogies) are shared between two such cars. A well flatcar is shown below.
A depressed center or well car carrying a heavy and tall load. Note the car rides on two 2-axel trucks which are in turn supported in part by two other 2-axel trucks connected with bolsters to facilitate movement over curves
Gondola Cars
Gondola cars are essentially open boxes on a flatcar. A typical gondola car has sides about 24" (61 cm) high. Gondola cars may be used to carry many types of solid goods, including stone, scrap metal, sand, equipment, coal and even fruit and vegetables such as potatoes. High-sided gondola cars (also called "bathtubs") may be used to carry lighter materials such as wood chips, or more of a given product such as coal. Sides may be as high as 10 feet (3 m). Gondola cars outfitted to carry coils of steel plate, pipe, wire, cable and such are called coil cars. Gondola cars may be uncovered or covered, usually with a flexible covering. A typical gondola car is illustrated below.
An HO-guage replica of a Norfolk and Western (NW) typical gondola car on the Shannondell Model Railroad
Because gondola cars carrying loose goods such as gravel or sand are somewhat difficult to unload, special equipment, called rotary car dumpers, have been devised to unload these cars. A gondola car is rolled onto a special section of track, and together with the track, is inverted to dump its load. Such equipment is illustrated below. A video (2.5 minutes) shows the operation of such equipment.
Kennecott Utah Copper LLC (KUC) rotary car dumper about 1972
Boxcars
Another common railroad car is the boxcar (also called covered goods wagon or van). Such cars are essentially closed boxes on a flatcar. Boxcars may be used to carry a very wide array of goods. In some cases, boxcars have special designs to accommodate the particular type of freight to be carried. Such designs accommodate livestock (cattle, horses, sheep, goats, hogs, poultry, even exotic animals -- stock cars), packaged goods, automobiles and many other items.
With the advent (ca. 1851) of the refrigerated boxcar (reefer), it became possible to transport vegetables and fruit, fresh meat, cheese, butter, beer, milk and so on (especially over long distances). Blocks of ice were initially used to refrigerate boxcars. The development of mechanical refrigeration units made possible temperature control and year-round shipment rather than being limited to winter months. Many types of goods, including human blood, fish, green onions, milk, strawberries, and certain pharmaceuticals can be transported via refrigerator car.
Boxcars, originally built of wood, are now made of steel or aluminum. Boxcars typically have doors on the long sides. Various door styles are used depending on the use of the car. Single or double doors, hinged or sliding doors, loose or sealing doors, and locking doors may be found on boxcars. In particular applications, such as automobile transport, where the boxcar is called an autorack, doors will be on the ends to facilitate loading and unloading. Autoracks may be double or triple deck.
Most boxcars can be loaded and unloaded using forklifts, which speeds the process and facilitates forwarding of goods. In the case of stock cars or autoracks, loading and unloading is usually unaided.
A typical boxcar is shown in the following photograph.
HO gauge double-door boxcar No. 40501 of the New York, New Haven and Hartford Railroad (NH) ca. 1956 seen on the Shannondell Model Railroad
Hopper Car
A hopper car is similar to a gondola car except that it is unloaded through hatches in its bottom. The lower part of the car's interior takes on a rectangular funnel shape that directs the contents toward the unloading hatch(es). The number of hatches ranges from two to six. In addition to the number of hatches, hopper cars are distinguished by being open to the elements or covered to protect the contents from the elements.Open hopper cars are used to carry crushed metal ores, crushed stone, coal and similar goods. Closed hopper cars may be used to carry grain, animal feed, cement, or other goods that require protection from the elements. An example of a covered hopper car is illustrated below.
HO-gauge model of a Terminal Grain Corporation (TRGX) covered 3-port hopper car on the Shannondell Model Railroad
Tank Car
In contrast with the railroad cars so far discussed, tank cars are designed to carry difficult-to-contain goods, such as gasoline, alcohol, various gasses, milk, orange juice and cement. Although all of these goods can be carried in gondola cars and boxcars if they are suitably packaged, they can only be carried in bulk in tank cars.
Tank cars are designed for various purposes. For example, tank cars designed to carry diesel fuel need to be strong enough to support the weight and be built of material that does not contaminate the fuel. Tank cars designed to carry acids such as sulfuric or hydrochloric need to be glass-lined to prevent the acids from dissolving the tank. Similarly, tank cars used to carry food-grade products (e.g., milk, juice, liquified egg) need to be lined with stainless steel or glass to protect the quality and integrity of the product. Some goods must be kept cool or cold, some must be carried under pressure. Some tank cars require special features to protect the shipped goods in the event of an accident or criminal attack. There are tank cars to accommodate any such requirement.
An example of a common tank car is shown in the following illustration.
A Trinity Industries Leasing (TILX) tank car No. 290344 carrying crude oil
Special Freight Cars
Special freight cars either exist or can be built to carry virtually any goods (within certain limits). Things such as airplanes, rockets, wind turbines, heavy machinery, large electric transformers and related items, boats, military equipment, rails and even railroad rolling stock can be carried on the railroads of today.
Special freight cars either exist or can be built to carry virtually any goods (within certain limits). Things such as airplanes, rockets, wind turbines, heavy machinery, large electric transformers and related items, boats, military equipment, rails and even railroad rolling stock can be carried on the railroads of today.
Design Limitations
There are certain limitations on the design and construction of railroad freight cars. One is the maximum allowed weight per axel on a train. This limitation can at least partially be overcome by using more axels per unit length of rolling stock. For example, a hopper car carrying 200,000 lbs. or 100 short tons of grain on two 2-axel trucks (bogies) will have an axel weight of 25 tons. This may be improved by using 3-axel trucks to yield an axel weight of 16.66 tons.
It is worth mentioning that the axel weight is ultimately transferred to the rails via a very small area of each wheel (no more than two square inches (25 square centimeters). For a 2-axel truck with an axel weight of 25 tons, what is the weight/square inch (square centimeter) on a rail?
Another limitation is called the loading gauge. This is a measure that defines the maximum height and width dimensions in railway vehicles and their loads. The loading gauge is determined by the structures along a rail line, including tunnel dimensions (height and width), bridge clearance dimensions, overhead catenary height and clearance of supporting structures, etc. The loading gauge determines the limits on loading as a result of prior railroad company decisions about structures the railroad has built or acquired. Loading gauge may easily be measured by using a physical structure that embodies the minimum height and width conditions on a given route and then simply passing the train through the structure. If the train passes through without incident, it will not encounter problems along its route.
At the same time, railroads use a structure gauge, also called the minimum clearance outline, that sets limits on the extent to which bridges, tunnels and other non-railroad infrastructure can encroach on rail vehicles. It specifies the height and width of platforms, tunnels, bridges, and other structures that could impede movement along the rails.
Yet another limitation is the radius of curvature of track along the rail line. Loaded freight cars must be able to negotiate all curves on a line from point of departure to destination. This is especially important for modern railroad cars that are typically much longer (up to 90 feet or 27.4 meters) than earlier versions.
There are certain limitations on the design and construction of railroad freight cars. One is the maximum allowed weight per axel on a train. This limitation can at least partially be overcome by using more axels per unit length of rolling stock. For example, a hopper car carrying 200,000 lbs. or 100 short tons of grain on two 2-axel trucks (bogies) will have an axel weight of 25 tons. This may be improved by using 3-axel trucks to yield an axel weight of 16.66 tons.
It is worth mentioning that the axel weight is ultimately transferred to the rails via a very small area of each wheel (no more than two square inches (25 square centimeters). For a 2-axel truck with an axel weight of 25 tons, what is the weight/square inch (square centimeter) on a rail?
Another limitation is called the loading gauge. This is a measure that defines the maximum height and width dimensions in railway vehicles and their loads. The loading gauge is determined by the structures along a rail line, including tunnel dimensions (height and width), bridge clearance dimensions, overhead catenary height and clearance of supporting structures, etc. The loading gauge determines the limits on loading as a result of prior railroad company decisions about structures the railroad has built or acquired. Loading gauge may easily be measured by using a physical structure that embodies the minimum height and width conditions on a given route and then simply passing the train through the structure. If the train passes through without incident, it will not encounter problems along its route.
At the same time, railroads use a structure gauge, also called the minimum clearance outline, that sets limits on the extent to which bridges, tunnels and other non-railroad infrastructure can encroach on rail vehicles. It specifies the height and width of platforms, tunnels, bridges, and other structures that could impede movement along the rails.
Yet another limitation is the radius of curvature of track along the rail line. Loaded freight cars must be able to negotiate all curves on a line from point of departure to destination. This is especially important for modern railroad cars that are typically much longer (up to 90 feet or 27.4 meters) than earlier versions.
Capacity
Modern railroad freight cars are designed to carry weights from 50 to over 100 tons (100,000 to 200,000 pounds or 45,359 to 90,718 kilograms). Of course, there are ranges of cubic capacity (for dry goods) or gallon (liter) capacity for liquids or length measure for long items. Keep in mind the Design Limitations discussed above. In general, railroads can transport almost anything, given these limitations and some lead time.
Modern railroad freight cars are designed to carry weights from 50 to over 100 tons (100,000 to 200,000 pounds or 45,359 to 90,718 kilograms). Of course, there are ranges of cubic capacity (for dry goods) or gallon (liter) capacity for liquids or length measure for long items. Keep in mind the Design Limitations discussed above. In general, railroads can transport almost anything, given these limitations and some lead time.
Construction Of Unpowered Railroad Cars
It is time to take a look at the actual construction of unpowered railroad cars. It is worth noting that "car" is short for "carriage". In many parts of the world, railroad cars are called wagons. Either term suggests that railroad cars (wagons) developed from existing wagons or carriages of a bygone era.
To build a flatcar, for example, a foundation frame is constructed of steel members such as I-beams, U-beams, tubular beams or something similar. The dimensions of these beams are determined by the load they are expected to support (up to 200,000 pounds or more).
The following diagram gives an idea of the construction of the foundation frame of a flatcar. Details are available (for a fee) at Association of American Railroads, Safety and Operation, Manual of Standards and Recommended Practices (MSRP).
It is time to take a look at the actual construction of unpowered railroad cars. It is worth noting that "car" is short for "carriage". In many parts of the world, railroad cars are called wagons. Either term suggests that railroad cars (wagons) developed from existing wagons or carriages of a bygone era.
To build a flatcar, for example, a foundation frame is constructed of steel members such as I-beams, U-beams, tubular beams or something similar. The dimensions of these beams are determined by the load they are expected to support (up to 200,000 pounds or more).
The following diagram gives an idea of the construction of the foundation frame of a flatcar. Details are available (for a fee) at Association of American Railroads, Safety and Operation, Manual of Standards and Recommended Practices (MSRP).
Diagram suggesting flatcar foundation frame construction and some under-frame components; scale is 1 inch = 5 feet
As the above illustration suggests, the end sill of the frame is about 10 feet long and must accommodate the coupler components (see following diagram). The foundation frame thus supports several under-frame components, including the
coupler, body bolster and brake system and above-frame components such as the decking, stake pockets, tie-downs, bulkheads and so on. Decking may be of steel or wood. All components must be situated so that weight symmetry about the long axis of the car is maintained.
Couplers
The coupler, as the name indicates, enables the unpowered cars to be connected to motive power and to each other. Freight trains of 100 cars are fairly common in the United States and other parts of the world (e.g., Mauritania, Australia, China). Longer trains are used but are not so common. Weight of the train must also be taken into account. Trains carrying 35,000 tons (70,000,000 lbs. or 31,751,466 kg) have been reported. Couplers must be strong enough to handle such massive loads.
Several types of coupler have been developed, including buffers and chain, link and pin, Albert coupler, Miller hook and platform, Norwegian, Lloyd coupler, Johnston coupler, bell-and-hook coupler and several others. In the United States, the Janney coupler is the standard and we limit our discussion to this type of coupler (now referred to as the Association of American Railroads (AAR) coupler).
Eli H. Janney invented the Janney coupler (also called knuckle coupler). Janney was awarded a patent for his invention in 1873 (U.S. Patent 138,405). This coupler is automatic in that no worker is required to be between cars during coupling and uncoupling.
The coupler consists of three main parts, the knuckle with its shank, a coupler pocket and a draft (or draw) gear, essentially a shock absorber. The component parts are illustrated below. The purpose of the draft gear is to absorb the pushing and pulling forces caused by the motion of the cars of a moving train. Typical travel distance is about 3.5 inches. This "slack" or "play" means that on a 100-car train, the last car moves, relative to the first one, about 3-4 minutes later.
Couplers
The coupler, as the name indicates, enables the unpowered cars to be connected to motive power and to each other. Freight trains of 100 cars are fairly common in the United States and other parts of the world (e.g., Mauritania, Australia, China). Longer trains are used but are not so common. Weight of the train must also be taken into account. Trains carrying 35,000 tons (70,000,000 lbs. or 31,751,466 kg) have been reported. Couplers must be strong enough to handle such massive loads.
Several types of coupler have been developed, including buffers and chain, link and pin, Albert coupler, Miller hook and platform, Norwegian, Lloyd coupler, Johnston coupler, bell-and-hook coupler and several others. In the United States, the Janney coupler is the standard and we limit our discussion to this type of coupler (now referred to as the Association of American Railroads (AAR) coupler).
Eli H. Janney invented the Janney coupler (also called knuckle coupler). Janney was awarded a patent for his invention in 1873 (U.S. Patent 138,405). This coupler is automatic in that no worker is required to be between cars during coupling and uncoupling.
The coupler consists of three main parts, the knuckle with its shank, a coupler pocket and a draft (or draw) gear, essentially a shock absorber. The component parts are illustrated below. The purpose of the draft gear is to absorb the pushing and pulling forces caused by the motion of the cars of a moving train. Typical travel distance is about 3.5 inches. This "slack" or "play" means that on a 100-car train, the last car moves, relative to the first one, about 3-4 minutes later.
The coupler pocket is fastened between the two center sills and houses the coupler shank, the follower, the draft gear and the yoke. The yoke surrounds the follower and draft gear and is connected by a draft key to the coupler shank. The control rod serves to lift or drop the knuckle pin to permit uncoupling. The striker limits the travel of the knuckle toward the pocket.
The following illustration shows an unpowered car (top) coupled to a locomotive (bottom).
The following illustration shows an unpowered car (top) coupled to a locomotive (bottom).
Photo showing coupling between a locomotive (front) and unpowered car (rear). The chain connects to a control rod that lifts a locking pin from the locomotive coupler; the control rod angled toward the left lowers the locking pin from the unpowered-car coupler (these control rods are inoperative when the train is in motion). The coupler pocket and part of the coupler shank are also visible
Braking
Another important under-frame element is the braking system. We have mentioned braking of trains elsewhere on this Web site (see, for example, Caboose History under Railroad History). Under normal operation, braking is needed to adjust the velocity of a train to prevailing conditions (traffic, curves, weather, etc.). Until the advent of the Westinghouse Automatic Air Brake System (ABS), braking was a manual affair with attendant hazards to the life and limb of workers called brakemen.
In 1869, George Westinghouse was awarded U.S. Patent No. 124,405 for a railroad braking system that used compressed air to operate the brakes on each railroad car. Over the years, various improvements have been made to this system, which is now universally employed on trains around the world. The current system is briefly described in the following paragraphs.
In a locomotive a compressor pump (see NYAB for example) produces compressed air at around 125–140 psi (8.6–9.7 bar; 860–970 kPa) which is stored in the main reservoir (in the locomotive), that supplies compressed air to a pipe, called the train line (also brake line) that extends the entire length of a train. The train line is connected to a car triple valve on each car. See illustration below.
Another important under-frame element is the braking system. We have mentioned braking of trains elsewhere on this Web site (see, for example, Caboose History under Railroad History). Under normal operation, braking is needed to adjust the velocity of a train to prevailing conditions (traffic, curves, weather, etc.). Until the advent of the Westinghouse Automatic Air Brake System (ABS), braking was a manual affair with attendant hazards to the life and limb of workers called brakemen.
In 1869, George Westinghouse was awarded U.S. Patent No. 124,405 for a railroad braking system that used compressed air to operate the brakes on each railroad car. Over the years, various improvements have been made to this system, which is now universally employed on trains around the world. The current system is briefly described in the following paragraphs.
In a locomotive a compressor pump (see NYAB for example) produces compressed air at around 125–140 psi (8.6–9.7 bar; 860–970 kPa) which is stored in the main reservoir (in the locomotive), that supplies compressed air to a pipe, called the train line (also brake line) that extends the entire length of a train. The train line is connected to a car triple valve on each car. See illustration below.
Schematic of a double-line automatic air brake system
The locomotive brake valve (automatic or driver's brake valve), provides for braking at the command of the operator (driver). Automatic braking occurs when the pressure in the train line (brake line) becomes less than the pressure at the main reservoir. This reduction in pressure in the train line is achieved 1) by the operator moving the control lever on the locomotive brake valve; 2) by some break in the train line (puncture or separation).
The train line or brake line, is composed of both metal pipe traversing the length of each car and flexible hose lengths that connect successive cars. Flexible hose is connected to the metal pipe by means if an angle cock (shut-off valve). The flexible hoses of two adjoining cars are connected together by means of F-Type Gladhand fittings. The air brake system is only operational if the angle cocks at the end of each car all are open except the one at the front of the locomotive and the one at the end of the train.
A second line, called the main reservoir pipe, also supplied from the main reservoir, is used to supply pressurized air to reservoirs on each car of the train. This line continuously supplies air to the car reservoirs until equilibrium is achieved and maintained. This insures that car reservoirs are fully charged independent of the train line.
A car reservoir is a tank mounted on the under-side of each car. The tank has two compartments, one for service (normal braking) and one for emergency application. The car reservoir makes each car independent of all others in a train for braking purposes.
The car triple valve is the brains of the system and is divided into service and emergency parts. This valve is so named because it performs three main functions: 1) it allows air into a reservoir ready to be used; 2) it applies the brakes and 3) it releases the brakes. In so doing, it supports certain other actions (i.e., it 'holds' or maintains the brake application and it permits the exhaust of brake cylinder pressure (brake release) and the recharging of the reservoir during the release). In this way, the car reservoir is insured of pressure from both the main reservoir pipe and the car triple valve.
The object of all of this braking system is the car brake cylinder, that applies pressure to the brake pad assembly (see illustration below) to slow or stop the train. The assembly may serve 8 or 12 wheels (two 2-axel or 3-axel trucks). Modern railroad cars may use disc brakes rather than shoe or pad brakes. The result is the same: friction is developed which slows or stops the train.
Illustration one side of the brake lever mechanism operated by the brake cylinder under a railroad car
Electronically controlled pneumatic brakes are the most recent innovation wherein the brakes of all the cars and locomotives are connected by a kind of telecommunication network, which allows individual and direct control of the brakes on each car, and reporting to the driver the performance of each car’s brakes (and other conditions). Electronic control overcomes the problem of propagation delay when air pressure is reduced in the train line. This means that brakes are applied more rapidly along the length of a train and also that there is less wear on the draw gear at the ends of each car.
Finally, each individual railroad car is equipped with a manual brake wheel to brake a car when it is isolated from a train.
Truck or Bogie
The third important under-frame element on a railroad car is the truck (bogie). A truck is what provides the ability for a railroad car to move and to negotiate curves. There have been many truck designs implemented in various parts of the world. Here we describe trucks similar to those manufactured by Amstedrail. For a more modern design, see bogies.
Each railroad car needs at least two trucks (but see Jacobs Bogies), each either of two or three axels. A 2-axel truck, together with a coupler and part of the braking system, can be seen in the following illustration.
The third important under-frame element on a railroad car is the truck (bogie). A truck is what provides the ability for a railroad car to move and to negotiate curves. There have been many truck designs implemented in various parts of the world. Here we describe trucks similar to those manufactured by Amstedrail. For a more modern design, see bogies.
Each railroad car needs at least two trucks (but see Jacobs Bogies), each either of two or three axels. A 2-axel truck, together with a coupler and part of the braking system, can be seen in the following illustration.
End view of a gondola car showing a truck supporting the car at the center plate
In this illustration the truck consists of an axel and two wheels supported by a truck frame that is attached to a truck bolster (large dark member behind the axel) that rests on coil springs. The truck bolster connects with a body bolster (dark under-frame member behind the coupler and end sill). The following illustration identifies the various components of a truck (bogie).
Components of a railroad car 2-axel truck
A truck has five principal components, two axel/wheel assemblies, two side frames and a bolster. An axel/wheel assembly consists of an axel with two wheels press-fitted to it at the gauge of the track on which it will travel. A roller-bearing end cap, also press-fitted, terminates each end of the axel. The axel/wheel assembly supports, via gravity, the side frame at the bearing cap.
The side frame is a one-piece cast steel part that bridges the two axel/wheel assemblies and contains a central pocket in which a group of coil springs, called load coils, support the ends of the truck bolster.
The truck bolster consists of a heavy cast steel member that links the two side frames together at the correct distance for the gauge of track on which the truck will travel. The bolster sits on the load coils so as to cushion the railroad car that will rest on the truck bolster. The bolster and side frame are held together by means of friction wedges and bolster gibs. At the center of the bolster there is a circular center plate with a rim and a center pin (not shown). At either side of the center plate is a side bearing and C-PEP (center plate extension pad) that reduces hunting and sway.
In order to link a truck with the under-side of the foundation frame of a railroad car, the car must be equipped with body bolsters (one for each truck). A body bolster is a heavy-duty steel member that is attached to the under-frame of the car. See following illustration.
The side frame is a one-piece cast steel part that bridges the two axel/wheel assemblies and contains a central pocket in which a group of coil springs, called load coils, support the ends of the truck bolster.
The truck bolster consists of a heavy cast steel member that links the two side frames together at the correct distance for the gauge of track on which the truck will travel. The bolster sits on the load coils so as to cushion the railroad car that will rest on the truck bolster. The bolster and side frame are held together by means of friction wedges and bolster gibs. At the center of the bolster there is a circular center plate with a rim and a center pin (not shown). At either side of the center plate is a side bearing and C-PEP (center plate extension pad) that reduces hunting and sway.
In order to link a truck with the under-side of the foundation frame of a railroad car, the car must be equipped with body bolsters (one for each truck). A body bolster is a heavy-duty steel member that is attached to the under-frame of the car. See following illustration.
The underside of the foundation frame of a railroad car showing two body bolsters, along with various structural members
At the center of the underside of the body bolster is a circular plate that fits into the truck center plate. A hole in the center plate accommodates the pin that protrudes from the truck center plate. The body bolster has side bearings (not seen in the illustration) that correspond with those on the truck bolster. That is the extent of the link between a car and a truck. Obviously, the trucks can pivot to facilitate travel over curves in the track. At the same time, it is clear that the linkage demands centering the mass of a load along the long axis of the foundation frame to prevent the car tipping over.
Mention the set-up on model cars
Also mention model car weight…
Also mention model car weight…