How Do Railroads Work?

How do railroads work? Because of their vast networks, different types, and logistics, many entities must work together for the railroad to operate efficiently. Locomotives must be maintained, rolling stock must be classified, and customers must be updated on the status of their shipments. 


Since the dawn of the industrial revolution, railroads have played a pivotal role in the advancement of modern society. They have revolutionized the way people traveled, and how goods were shipped. In their infancy, rail travel was a spectacle, as trains oftentimes traveled at previously unknown speeds. This speed and efficiency have allowed consumers to receive goods quicker than ever before, thus, fueling the mass production of various products.

According to the Association of American Railroads (AAR), five million tons of freight are moved across North America daily. Many often ponder how the railroad works, and is able to transport goods in bulk, all while ensuring that each piece of rolling stock reaches the desired destination. An assortment of classification yards and technology assist in these endeavors, as technology such as GPS and RFID technology have emerged in the modern era. Maintenance crews for the infrastructure, and mechanical engineers for the locomotives and rolling stock are ever prevalent, as these individuals represent the backbone of any railroad company.

Jeff Hampton

Classes of Railroads

In North America, there are various classes of railroads and each railroad in divided into their respective classes. The railroads are placed into their respective class by annual profit and system mileage. For example, many of the large rail corporations in North America such as Norfolk Southern, CSX, BNSF, Union Pacific, Canadian National and Canadian Pacific, make up most of the continent’s freight rail traffic.

Class 1: According to InTek Freight & Logistics Inc, a Class 1 railroad is defined as a railroad that collects $447,621,226 in annual revenue. Additionally, to be considered a Class 1, a rail company must have trackage in the United States. According to, Class 1 railroads accrued 68% of freight mileage in North America, leaving the remaining 600 smaller railroads to cover just 32% of North American freight mileage.

Class 1 Railroads- BNSF Railway, CSX Transportation,Canadian National, Canadian Pacific, Kansas City Southern, Norfolk Southern, and Union Pacific.

Class II: Also referred to as a Regional railroad, Class II railroads are defined as a railroad accruing a profit of at least $35,809,698 (InTek). According to Association of American Railroads, regionals account for just 10% of North America’s railroad workers, and have at least 350 miles of track. In the United States, Regional railroads are present in every state in the lower forty-eight, and Alaska.  Some notable railroads that fall into this category are Montana Rail Link, Pan Am Railways, Utah Railway, Alaska Railroad, New York Susquehanna and Western (NYS&W), and the Wheeling and Lake Erie Railway.

Terminal Railroads- Terminal railroads are smaller railroads utilized to transport rolling stock between two large railroads, or at a port or container hub. Some notable terminal railroads are the Belt Railway of Chicago, Galveston Railroad, and jointly owned CSX and Norfolk Southern, Conrail Shared Assets Operations (CSAO).

Passenger and Commuter Railroads- passenger and commuter railroads are prominent throughout North America, most notably in busy metropolises and populated areas. In the United States, Amtrak commands much of the nation’s passenger traffic, however, only 30% of its trains operate on Amtrak owned right-of-way, primarily on their Northeast and Keystone Corridors. While Amtrak operates in the United States, Via Rail operates in Canada on various commuter and transcontinental routes.

Bill Johnson


Locomotives were always impressive machines, as their sheer power and size is sure to attract the attention of even the casual onlooker. Throughout the nearly 200 years of their existence, locomotives have advanced from the earliest steam trains in the early 19th century, to the technologically advanced locomotives of the modern era. Upon dieselization in the mid-twentieth century, locomotives became easier to operate, as diesel locomotives do not require hours of preparation to operate, as opposed to a steam locomotive.

When viewing a passing train, an onlooker may notice that more than one locomotive is on the head end, however, the train crew is only present in the lead locomotive. This technology, called multiple unit operation, was perhaps the most convincing aspect of dieselization. Locomotives are linked together via a series of cables, both electrical and pneumatic, which link together the locomotives in the consist, allowing multiple locomotives to haul the train with a single crew in the leader.

Locomotives are superior haulers, as many trains in North America can stretch well over a mile long, and carry in excess of one-hundred cars. With their superior strength and capabilities, advances in locomotive design and technology have propelled the industry into becoming the backbone of the economy, and the leading mode of land transport.

Bill Hooper

Rolling Stock

Rolling stock is the freight or passenger cars hauled by a locomotive. Rolling stock can range from the simplest freight car to a long distance sleeper car. Freight rolling stock can haul anything from food and clothing, to chemicals and fuel, such as coal and oil. Many of the freight cars in North America are owned by leasing companies who either lease their stock to the railroads, or utilize the railroads to ship their rolling stock to their destination.

With the vast array of rolling stock, it is imperative that maintenance on the cars is conducted regularly. Rail cars must meet the minimum safety requirements set forth by the AAR and the Federal Railroad Administration (FRA), who impose steep fines if a railroad or leasing company violates these requirements.

Classification Yards

Classification yards are important to any large rail system, as each rail car is directed onto the correct train, ensuring the car gets to its destination. There are a few different types of classification yards, one is called a flat yard, where cars are pushed by a locomotive and lightly coast to their specific track.

Another common type of classification yard is a hump yard, where cars are rolled down a hill and slowed by mechanisms along the track. The hump is an man-made hill where cars are released, and are rolled down the “lead” track, which includes a mechanism to slow the car before entering into a set a switches called the “ladder” track, which then is directed onto the desired yard track, and into their respective consists. The force of gravity is important in this type of yard, as it is the main form of power employed after the car is released.

Jeff Hampton

Because some of the busiest yards are capable of processing between 6,000-7,000 cars daily, various safety measures are put into place to prevent accidents. Speed controls, radio communication, and signaling are commonplace in these types of yards to ensure safety and efficiency are in check.

Because classification yards are imperative to rail operations, they are quite large and can encompass hundreds of miles of track. World’s largest railyard, Union Pacific’s Bailey Yard in North Platte, Nebraska, includes 315 miles of track, and stretches over 2,000 acres of land. Bailey Yard handles 10,000 cars daily, and has the capacity to provide routine maintenance to 9,000 locomotives monthly.


A railroad encompasses a large range of customers, from large corporate firms to small businesses. According to the AAR, railroads charge shippers using a strategy called, “differential pricing”, where rates are dependent on the shipping options that are available to a customer. If a shipper has alternative modes of transport available, the railroad would charge the customer less. If the customer has a limited number of transportation options, the railroad would charge them more. Some of the largest companies include Cargill, who provide goods such as agricultural products and industrial supplies, ships 118 million gallons of ethanol on the railroad annually, which equates to roughly 3,900 rail cars.


Railroad signals are imperative on any rail system, as they regulate the flow of rail traffic, and must be operating effectively at all times. Much training on signal aspects are conducted for new locomotive engineers and conductors, as it is imperative for their safety, as well as communities surrounding the railroad. Railroad signaling in North America is a complicated and in-depth system, requiring much training to prospective locomotive conductors and engineers on their territory.

The various signaling systems have evolved from hand signals, utilized in the pioneering days of the railroad. Additionally, many of the operating rules utilized trace their origins to the early British practices. In the early days of railroading, when railroads were scarce, the signaling system was simple, however, with the various expansions in the nineteenth and early twentieth century, railroad signaling evolved into a rather complicated entity.

Railroad signaling ensures that a section of track is clear and safe for travel, and ensures that the railroad operates safely. There are various types of signals of different sizes, colors, and aspects, each of which serve a vital purpose. In addition to the line-side signals, most modern locomotives have signals inside the cab the alert the crew of an approaching signal aspect.

Jeff Hampton

Block Signaling- block signaling is a type of automatic signaling in which the railroad is divided into a number of blocks, which allows the automatic block signals to govern the traffic that moves through the block. These types of signals assist in keeping trains at safe following distances, which therefore, reduces the chance of a rear end collision. In the early days of railroading, the blocks were operated manually, which was introduced on the Pennsylvania Railroad in the mid-nineteenth century. Before block systems became commonplace, telegraph communications between the train crews and dispatchers governed multiple train movements on a single track.

Absolute- absolute signals are controlled by a dispatcher and govern an interlocking diagram. These signals default aspect is stop and trains are not permitted to pass the stop aspect without special permission from the dispatcher.

Semi-Automatic- a semi-automatic signal commonly mimics an automatic signal, however, it can display a restricted proceed type aspect.


Railroad maintenance is constantly at the forefront of the industry, as it keeps locomotives, rolling stock, and infrastructure operating at peak performance. Many maintenance facilities are located throughout a railroad’s system, ensuring the equipment is in its peak condition. Locomotive and rolling stock maintenance is imperative in daily railroad operations, as maintaining equipment boosts efficiency and allows the railroad to lessen delays in shipments.

Maintenance performed on a locomotive ranges from axle and traction motor replacement, to prime mover work. Sometimes, heavy rebuilding will be done on locomotives to return them to as-new condition. One of the largest repair facilities in North America is Norfolk Southern’s Juniata Shops, which handles maintenance for Norfolk Southern locomotives and rolling stock. In fact, the work at Juniata is so superior, other railroads send their locomotives there for heavy maintenance and rebuilding.

In addition to locomotives, track and other infrastructure must be monitored and maintained. Track workers oftentimes replace broken rails and rotten ties. Special track maintenance vehicles ride along the rails with lasers and other technology to inspect the integrity of the ballast and rails. Bridges and tunnels are inspected by professional inspectors, who look for any defects or abnormalities that might be present.


Lifelong Rail Enthusiast and Owner of Worldwide Rails

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