The life of a railroad crosstie sees nearly 20 years of service. Through harsh conditions such as rain, heat, and snow, the backbone of the rails is built to last. But just how long should they carry the load?
Researchers from the Forest and Wildlife Research Center and the Railway Tie Association have set out to determine how durable railroad ties are by exposing them to different conditions and preservatives.
Dr. Beth Stokes, an assistant professor in the Department of Sustainable Bioproducts, said her team aims to determine the reliability of the wooden crossties being produced through research.
"Our research will determine if we can produce a reliable, structurally sound product that is going to last more than the average lifespan once we put it into use in a track. How can we tailor that product to the needs of different environments? So, the overall idea is that we expose the ties, treated with various preservatives, to conditions they would experience while in use," Stokes said.
The studies—one in its eighth year and the other in its twelfth—are carried out at the John W. Starr Memorial Forest's Dorman Field Site outside of Starkville and at the Formosan Termite Testing Facility at the Mississippi Agricultural and Forestry Experiment Station's McNeill Research Unit in coastal Mississippi. The team looks at full-sized railway ties made of different wood species, such as red oak and sweetgum, which have been treated with different protective systems. The ties are brought to the field site and placed on a prepared surface where they are subjected to any weather conditions that occur during the length of the test. The ties will go through rain, wind damage, high humidity, and possibly snow or ice.
These studies will go on for up to 20 years, each tie being checked twice a year. When checked, the team looks at the amount of damage that has occurred, whether termites have moved in, if there is any decay occurring, the color of the ties, whether the metal plates have loosened, and if they remain structurally intact.
Stokes, one of the principal investigators on the projects, said the team wants to understand how long-lasting the resources are, and how they can be best used.
"One of the things we're assessing is how to make crossties as sustainable as possible," Stokes said. "We want to use our wood resources most appropriately across North America, and that's the direction we're moving in: proving the durability of wooden ties over other materials such as concrete or steel."
Once a crosstie has been removed from the tracks, there are still a number of ways they are used. From retaining walls to landscape timbers, crossties retired from the track still have usefulness, and perhaps one of its most important services is its ability to sequester carbon.
Ashley Goodin, the executive director of the Railway Tie Association, said the data from this research conveys the value of wooden crossties to not only the industry but also in terms of forest management.
"This data helps us communicate the value of a wooden crosstie and its longevity to the railroads for its use," Goodin said.
"Wooden ties are great tools for carbon sequestration, so you are talking about responsible forest management practices allowing you to harvest timber and use that timber for a service life of 20-25 years in track before it is turned into another valuable product."
Goodin said the research reinforces the significance of wooden crossties, as well as Mississippi State's partnership in the work.
"The third-party research from MSU continues to reinforce that wooden crossties are the best choice for the railroads," Goodin said. "This also adds value to the research program between Mississippi State and the USDA Forest Products Laboratory, and it reinforces MSU;s validity, as well as their due diligence and care in these long-term studies that are vital to our industry."
This research is funded by the Railway Tie Association and member companies of the Southern Pressure Treaters' Association.