For well over a century, freight cars have transported goods, raw materials, and other commercial cargo on freight rail networks spanning the entire country. In many ways, the development of the freight rail system in the U.S. has paralleled the ebb and flow of this country’s economic growth. And carrying the load, in a manner of speaking, are highly specialized rail transport equipment known as freight cars.
There are 12 major classifications of freight cars that are designed to transport different types of cargo. They are:
- Covered Hoppers
- Coil Cars
- Intermodal Containers and Trailers
- Open-Top Hoppers
- Refrigerated Boxcars
- Tank Cars
- Well Cars
According to industry experts, rail freight is not only an effective means of transporting large loads of cargo across great distances, but it is also the most fuel-efficient means of moving freight over land. Chances are if it can be transported via rail, there is a specialized type of freight car to handle the load securely. Read on to learn about the 12 major types of freight cars and just how specialized they can be.
These are the 12 Major Types of Freight Cars
Whether they are used to transport raw materials from suppliers to manufacturers or to anchor the final leg of finished goods’ journey to the marketplace, freight cars play an indispensable role in ensuring that the stream of commerce keeps flowing.
And to keep pace with the ever-expanding diversity of goods and materials that are shipped via rail, freight cars have evolved from simple platforms on axles to sophisticated purpose-built transportation vehicles that get the job done safely and efficiently.
Here are the 12 major types of freight cars traveling along rail networks across the country today.
By one industry estimate, there were roughly 17 million cars and light trucks that were sold in the U.S. in 2019. And at some stage of their journey from factories or ports to their owners’ driveways and garages, approximately 75% of these vehicles (which equates to over 14 million) were transported on the nation’s rail systems in highly specialized freight cars known as autoracks.
From compact sedans to luxury SUVs, autoracks are responsible for safely and securely moving automobiles of all shapes and sizes from one point in the stream of commerce to another. Autoracks are fully enclosed conveyances of enormous proportions, capable of transporting anywhere from several vehicles to several dozen in a single car. There are four main types of autoracks:
- Uni-level autoracks have a single deck and are used to transport large vehicles like tractors, buses, and RVs
- Bi-level autoracks contain 2 decks and can accommodate up to 10 trucks, SUVs, and mini-vans
- Tri-level autoracks have 3 decks and are designed to carry up to 15 sedans
- Automax autoracks can be configured to have 2 or 3 decks and can hold up to 26 vehicles
When strung together, a single train with multiple autoracks linked together can easily transport several hundred vehicles. Thus, where large numbers or great distances are involved, autoracks are the perfect solution for transporting vehicles over land efficiently and reliably.
Perhaps the most recognizable type of freight car is the boxcar. With their boxy rectangular shape, boxcars are the jacks-of-all-trades in the freight game, offering unparalleled flexibility in the transportation of goods, products, and materials. Boxcars are used to transport a broad and diverse range of cargo, including:
- Palletized goods and materials
- Various types of paper products, including pulp and newsprint
- Appliances and equipment
- Building materials
- Food products
- Auto parts
To accommodate different types and sizes of loads, boxcars can be found in varying lengths and heights:
- 50’ standard boxcars are 50 feet in length, 9 ½ feet wide, and nearly 11 feet high and can transport 70 to 100 tons of cargo
- 50’ high-roof boxcars have an additional 2 feet of clearance inside (13 feet) and are designed to carry special commodities like bulk paper rolls
- 60’ standard boxcars are 60 feet in length and the extra length makes them ideally suited for lighter, bulkier cargo
- 60’ high-roof boxcars are commonly used to transport appliances, auto parts, and bulky items
- 86’ auto boxcars are well-suited for large, bulky cargo like insulation and paper products
By one industry estimate, there are roughly 105,000 boxcars in service on the nation’s rail networks, but as more specialized freight cars, like tankers and covered hoppers, gain in popularity, recent trends have seen the number of boxcars in active duty dwindle. In fact, of the 105,000 boxcars that can be called into service, nearly 20,000 are in storage.
Centerbeams are specialized freight cars designed to carry bundled commodities like lumber, fence posts, wallboard, and other dimensional building supplies. Centerbeams are essentially long platforms with a heavily-fortified center I-beam that provides structural strength. Some centerbeams also have bulkheads at both ends of the car for additional stability longitudinally (i.e., to prevent commodities from shifting forward or backward on the car).
Here is how a typical centerbeam freight car measures up:
- Length: approximately 80 feet
- Maximum load height: 11 ½ feet
- Load limit: 224,000 pounds
One of the advantages of centerbeams, aside from their impressive cargo capacity, is the fact that they can be loaded and unloaded from both sides of the freight car simultaneously. The drawback to the feature, however, is that loads must also be distributed evenly on either side of the center I-beam to prevent leaning and instability during transit.
Coil cars are purpose-built for transporting coiled (rolled) steel which has an incredibly broad range of applications in manufacturing and construction. The list of products that rely upon steel coils in their fabrication is extensive and thus the importance of this building material cannot be overstated. Here are just a few examples of everyday items made from rolled steel:
- Structural steel members (e.g., I-beans, H-beams, trusses, rafters)
- Electronic equipment
- Automotive parts
- Metal stamped materials
Thus it comes as no surprise that freight cars designed specifically to transport this valuable and heavily relied-upon resource are in widespread use today. Given the enormous girth and weight of steel coils, coil cars are typically found in two configurations:
- Longitudinal coil cars can hold extra-large coils (measuring up to 84” in diameter) or multiple coils laid end to end, running the entire length of the car which measures around 52 feet
- Transverse coil cars have troughs built into them running across the width (from side to side) of the car and support steel coils within these structures
- To accommodate a full range of coil sizes, transverse coil cars come in 5-trough and 10-trough configurations
All told, coil cars are capable of transporting loads ranging from 220,000 to 231,000 pounds. Despite consisting of durable steel, coils are vulnerable to the elements and for this reason, coil cars are usually covered.
Among the more widely used types of freight cars today are covered hoppers, which are similar to boxcars in appearance but are specifically designed to transport enormous quantities of bulk dry goods. Like boxcars, covered hoppers have rigid sides and fixed ends along with a sealed roof to protect the contents of the car from weather and the elements.
But where covered hoppers differ are the ways in which their cargo is loaded and unloaded. Within the protective roof on each car are hatches that once opened, enable things like grain, rice, or sand, to be quickly loaded. As far as unloading, this is done via gated chutes at the bottom of the cars.
Covered hoppers are used to transport bulk commodities like:
The main advantages of transporting certain types of bulk dry materials in covered hoppers are:
- The commodities are protected from the elements (e.g., rain, sun, contamination) by a tight-fitting cover that fully encloses the hopper
- Internal bays (numbering from 2 to 4 per covered hopper) can be loaded separately, allowing for different types of products within the same car
- The heavier the commodity (e.g., cement or gravel) the fewer the number of bays within each car so as to stay within safe weight limits
- Unloading is achieved through gravity-fed chutes located on the undersides of the cars (each bay has its own dedicated chute)
Like other types of freight cars, there is a specialization within the covered hopper category to address the unique requirements of certain types of cargo. There are three types of covered hoppers in use today:
- Small covered hoppers run 42 feet long and can transport anywhere from 207,000 to 233,000 pounds of heavy bulk products like sand, cement, and gravel, in their 2 internal bays
- Large covered hoppers measure 60 to 65 feet in length and can transport from 197,000 to 224,000 pounds of lighter commodities like corn, wheat, barley, and fertilizer in their 3 internal bays
- Food-grade covered hoppers are also 60 to 65 feet long, can transport up to 222,000 pounds per car, and typically have 3 to 4 internal bays with special liners to safely transport food products like rice, malt, and sugar, without fear of contamination
When it comes to transporting large quantities of dry goods that are susceptible to damage from the elements, covered hoppers provide a secure and efficient means of transporting valuable cargo over the nation’s freight rail networks.
Flatcars are among the oldest types of freight cars and have been in use since hauling large stones across the New England states in the early 1800s. With their signature flat-deck structure, flatcars are primarily used today to transport virtually any type of cargo that can fit on the car and withstand exposure to the elements and unfavorable weather conditions (since they are uncovered).
Examples of the type of freight that flatcars can carry include:
- Large vehicles and equipment like tractors
- Heavy bulky items like various types of commodities
- Construction materials like beams and posts
- Industrial parts
- Rails for railroads
A popular variant is the bulkhead flatcar which has reinforced walls at both ends of the car to prevent forward and backward shifting of cargo during transit. Throughout much of the 20th-century flatcars ranged from 40 to 50 feet long but today it is not uncommon to find flatcars that exceed 80 feet in length.
Gondolas are the true workhorses of freight cars as they are designed to carry high-density bulk materials and commodities. They are essentially uncovered boxcars but with shorter, sturdier sidewalls which makes them ideal conveyances for heavy materials that would be challenging to transport in most other types of freight cars.
Most gondolas are rated to hold and transport approximately 1,000 pounds per square foot. Here are some examples of the types of cargo that gondolas are relied upon to move along rail networks:
- Iron ore
- Lumber and logs
- Steel and scrap metal
While the use of gondolas is limited to the types of cargo that can be subjected to the elements (since gondolas are typically uncovered), the low clearance of their walls facilitates the quick loading and unloading of heavy, dense materials.
Intermodal Containers and Trailers
One of the most significant developments in shipping and logistics was the emergence of intermodal equipment like containers and trailers. Basically, intermodal equipment can be transferred between various modes of transportation – namely, cargo ships, trains, and trucks – without the need for unloading and reloading the cargo held within.
Intermodal containers and trailers are used to transport a wide range of goods, materials, and commodities, including:
- Food and beverage products
- Agricultural products
- Consumer goods
- Materials used in the manufacturing and construction industries
By virtue of cargo remaining in the same container or trailer throughout the course of its journey, a tremendous degree of shipping speed and efficiency results.
Open Top Hoppers
Open top hoppers are the epitome of no-nonsense freight cars. While autoracks and coil cars transport specialized cargo like cars and rolled steel, open top hoppers are tasked with moving bulk commodities that might not be as glamorous but are vital resources for key industries like manufacturing and construction.
These are the types of cargo that are transported in open top hoppers:
- Wood chips
Open top hoppers often feature multiple inner compartments, each with its own gated chute for easy unloading. Lengths of these cars can vary from 37 up to 57 feet and cargo capacities can range from 166,000 to over 243,000 pounds.
For perishable food items that must be maintained at certain temperatures throughout their journey to market, refrigerated boxcars (also known as “reefers”) provide climate-controlled environments for consumable items like:
- Fresh produce
- Dairy products
- Frozen meat and seafood
Because of the nature of their cargo, refrigerated boxcars often require logistics involving cold storage facilities in order to maintain proper cold chain custody (i.e., an unbroken chain of temperature management throughout perishable goods’ journey).
The fact that perishable goods are regularly transported via refrigerated boxcars across the nation’s rail networks is a testament not only to the advanced engineering that goes into specialized freight cars like reefers but also to the reliability of the freight rail system as a whole.
Commonly referred to as tankers, tank cars are highly specialized freight cars designed and engineered to transport liquids and liquefied products. Featuring a horizontally-oriented cylindrical shape with a heavily reinforced construction, tank cars typically have a domed loading feature on top with an integrated safety valve and a discharge mechanism at the bottom of the tanker.
As far as the types of liquids that can be transported via tank cars, here are a few examples:
- Oil and petroleum products
- Refined petroleum products like gasoline and kerosene
- Industrial chemicals including chlorine and ammonia
- Liquid food products like edible and cooking oils
- Dairy products like milk
Depending on the contents, tank cars can be pressurized or non-pressurized, insulated or non-insulated, and even cryogenic or non-cryogenic. It is also important to note that in most cases, tankers that are used to transport a particular type of liquid could not be used to carry another (e.g., a tanker hauling petroleum on one leg of a journey would not be expected to transport vegetable oil on the return trip).
With the advent of intermodal shipping came the need to make the transport of intermodal containers via rail more efficient. Enter the well car, which is essentially a flatcar with a deep depression (the “well”) lying between the wheel axles.
This unique well design creates several advantages:
- An intermodal container can be nestled snugly and securely in the car by sitting in a depression
- Because the base container sits closer to the ground, a second container can be stacked on top for doubled capacity
- The lower center of gravity (as opposed to conventional flatcars) of double-stacked containers sitting on a well car not only affords greater stability while in transit but also ensures safe tunnel and bridge clearances
Well cars come in three main configurations that correspond to varying container lengths:
- 40 feet
- 48 feet
- 53 feet
A fourth type of wellcar features integrated hitches that allow semi-trailers to be hoisted and secured on top of the freight car for transport.
So common is the practice of double-stacking intermodal containers that there are entire trains comprising well cars configured in this manner running every day (these are known as “stack trains”). By some estimates, as much as 70% of intermodal shipping in the U.S. utilizes double-stacking on well cars.
Although it has been running for well over a century, the freight rail system in the U.S. is considered to be the world’s largest, safest, and most cost-efficient freight shipping system, with roughly 140,000 route miles of track managed by 7 class-1 railroads, 22 regional operators, and 584 local railroad companies.
Through the years a number of advancements have been made and the 12 major types of freight cars that are currently in use today are a testament to the constant innovation of the $80 billion freight rail industry.