Spanning coast to coast, America’s 140,000-mile freight rail network connects the nation’s supply chain and provides consumers and businesses with a safe, efficient and cost-effective way to ship the things we use every single day. To maintain and expand such a critical network, America’s freight railroads plan to invest $25.5 billion of their own money – not taxpayer dollars – in 2013.
While railroad tracks might look much like they did 100 years ago, advanced technology has made railroad infrastructure stronger, safer and more reliable. A railroad track consists of two parallel steel rails set a fixed distance apart, called the gauge. The rails are connected to each other by railroad ties, which may be made of wood, concrete or other material. The rails are fastened to the ties by spikes, bolts or special clips, depending on the type of tie. The ties are set into ballast, which consists of stone particles that help transfer the load of the trains to the underlying foundation.
Railroad track: Parallel steel rails laid on wooden ties.
Rail: Set of steel bars placed end to end in two parallel lines.
Spike: Piece of metal used to attach the tie plate pad to the rail.
Tie: Wooden or concrete laid perpendicular to and beneath the rails.
Tie plate: Piece of metal that supports the rail.
Ballast: Crushed rock or gravel placed beneath the ties to provide a foundation for the track.
Thanks to advancements in steel manufacturing, the quality of steel used for railroad track has gotten much better. Today, the lifespan of rail averages 50-60 years, depending on how much freight is transported annually on the line and other factors. Railroad companies inspect their track using specialized equipment such as track geometry cars and rail defect detector cars, as well as visual inspections. These specialized technologies use laser sensors to detect track wear and tear and alert railroads to potential defects, enabling them to schedule maintenance in a safe, timely and cost-effective manner.
Maintenance of Way employees lay rail, install crossties and build track to ensure trains run safely at optimum track speed. More than 35,000 railroad employees nationwide perform railroad track and bridge work. When rail is scheduled for replacement, a rail gang is sent to the location to do the work. Here, Norfolk Southern has dispatched its Super Rail Gang to a site in Georgetown, KY. This gang, composed of 78 employees and 42 pieces of equipment, has the ability to lay dual ribbons of rail. The machines they use — which stretch for more than a mile from end to end — have greatly enhanced efficiency. In a six-to-eight hour day, the Super Gang can lay eight to ten quarter-mile long ribbons of rail.
Safety is the railroad industry’s number one priority. Before work on the tracks even begins, Maintenance of Way crews hold a safety briefing and a group session of calisthenics exercises before breaking up into smaller groups for their job briefings. The daily safety briefing provides workers with information about where they will be working for the day, their authorization to occupy the track for maintenance work — or track time — and instructions regarding train speed through the maintenance area — or slow orders.
When it’s time to replace railroad rails, the work starts weeks in advance when a work train unloads 1,440-foot ribbons of rail (over a quarter mile long), tons of ballast, tie plates, kegs of rail spikes and bags of rail anchors along the track. It’s called “setting the table.”
Once the ribbons of rail are laid out, a Multi-Purpose Crane Threader Cart (shown here) is used to move the rail that was deposited on the side of the track into the cradles in the center of the track to begin replacement. Donny Calhoun (inset), a foreman with Norfolk Southern, helped develop this technology.
The Super Gang uses a specialized machine called a Rail Polisher to grind the new railroad track. Grinding the track removes rust and debris from the new track, allowing the electrodes on the weld head to make proper contact and ensuring that the rails will adhere properly when welded together. This Rail Polisher is being operated by Britt Robinson from Mars Hill, NC.
Next, the Super Gang will use a machine called a Flash Butt Welding Machine to weld the 1/4 — mile-long ribbons of railroad rail together. Continuously welded rail — also called ribbon rail — has greatly improved safety and efficiency on the railroad. Since the number of joints are few, this track is extremely durable and needs less maintenance. Prior to its advent, 39-foot sections of rail held together by joint bars were used. Here you can see what the ribbons of new rail look like once they have been welded together.
The concept for the machine was developed in the field by Norfolk Southern’s Super Rail Gang. Built in the company’s Charlotte Roadway Shop, the Buffalo Machine is used to adjust expansion and contraction of ribbon rail using hydraulic cylinders, which is much more efficient than the system of blocks and cables. The Buffalo Machine gets its name from its brute force capabilities that allow it to maneuver 2 or 3 ribbons of rail at a time. Rail weighs anywhere from 85 to 141 pounds per yard.
The Spike Puller Machine is then used to pull out the spikes anchoring the old railroad track to the railroad ties. Before the advent of this machine, spikes were pulled by hand, which was very labor intensive and time consuming. There are at least 12,800 spikes per mile of track and additional spikes are often installed on curves to provide the rail with enhanced stability.
The Super Gang uses a machine called a Wide Gauge Threader to take the old rail and move it toward the outside of the ties so that the new rail can be pushed into place on the railroad ties. The old rail is either reused on a branch line or in a rail yard, or recycled into new steel products. Here, NS’ Trackman Bryson Lane from Newport, TN operates the Wide Gauge Threader.
Rail workers, in machines called Plug Buggies, then insert wood plugs into the holes in the railroad ties left behind by the old railroad spikes in the railroad ties. Plugging the holes ensures that railroad ties do not deteriorate prematurely and that they hold the new railroad spike securely in place.
A Dual Cribbing Machine is used to clear ballast away from the area where the new rail is being laid so that it does not interfere with the placement of the new rail and provides an open area under the rail for the operation of the rail anchor machines.
New railroad tie plates are then put into place on the ties using a Plate Lining Machine (left). Railroad tie plates are used to hold the rail in place on the tie. Railroad spikes are driven through that tie plate and into the railroad tie, securing the track to the tie. On average, there are about 6,400 plates per mile of track. These plates, depending on the design, weigh anywhere from 25 to 35 pounds. A Railroad Tie Adzer (inset) is used to prepare the surface of the tie plate area before the tie plates are put in place.
The Super Gang uses a Standard Gauge Threader, otherwise known as “Sergeant,” to put the new rail into place on top of the railroad ties and tie plates. Railroads can re-lay two to two-and-a-half miles of rail per day.
When new rail is laid, the rails are heated to a certain temperature, usually between 100 and 110 degrees Fahrenheit, to prevent expansion or contraction of the rails during winter or summer. To do this, the Super Gang uses a machine called a Rail Heater. This machine includes a propane tank, which holds the fuel needed for the heaters.
A Nipper Spiker Machine uses hydraulic pressure to drive the spikes through the tie plates and into the railroad ties. Before these types of machines were invented, all spiking was done by hand. It was a time-consuming and labor-intensive process and often a refined area for many railroad workers — historically known as “gandy dancers.”
The Anchor Applicator Machine applies new tie anchors to the rail. Tie anchors prevent the rail from moving longitudinally along the track, a situation that is referred to as track buckling in the rail industry.
Finally, the Super Gang uses a Switch Ballast Tamper Machine to “tamp” or pack the track ballast under railroad ties to make the track more uniform. Ballast consists of granite stone that has been crushed to standard dimensions. It is used to transfer the weight of trains to the underlying foundation, which helps keep the track in place and also facilitates drainage of water. Railroads spent $1 billion on ballast alone in 2011.
With a 140,000-mile outdoor network, railroading is one of the nation’s most capital-intensive industries. In 2013, railroads plan to spend $24.5 billion to do things such as maintain bridges, lay new track, purchase equipment and upgrade signal systems. In fact, railroads spend more than five times the amount of the average U.S. manufacturer on capital expenditures. As the demand for safe, cost-effective freight transportation grows, America’s freight railroads will continue to maintain and expand the track on which America’s economy rides.