Working on the Railroad: Borates Protect Wood Crossties for Safety and Sustainability

:: Monday, October 7, 2019 :: Posted By Frank Wawrzos

For 200 years, railroads have been the foundation of transportation, shipping, and commerce in North America. Today, passenger trains still carry people across cities and across the continent. By offering high-quality service at affordable costs, railroads have remained an indispensable freight transport mode, carrying nearly 19% of all freight and integrating with today’s sophisticated intermodal transport systems.

Incredibly, this foundational and essential infrastructure runs on one of the simplest technologies imaginable: The railroad crosstie.

Today, borates play an integral role in the protection, safety, and sustainability of crosstie production.

Railroad crossties: A renewable foundation for transport

The history of rail in North America has been both romanticized and vilified, but throughout its history, rail transport has been an integral part of our cultural and economic fabric. And, it’s amazing to consider that all of this history has run reliably on simple, durable wooden crossties.

Crossties are the heavy wooden beams that support the rails trains run on. Each tie is hewn from hardwood and measures 7 inches by 9 inches by 8 feet. Today there are:

  • More than 200,000 miles of railroad track in use in the United States
  • Approximately 3,249 ties per mile
  • Between 700 and 800 million ties in service

According to the Railway Tie Association, more than 17 million ties were installed in 2016, of which more than 3 million were replacements.

If those numbers are hard to fathom, consider this: the number of ties replaced would be dramatically higher without the wood protection measures that tie producers employ.

From the inside out: Borates for wood protection in crossties

After the completion of the first transcontinental rail line in 1869, railroad use increased rapidly. The ties used through the early years of that expansion into the early part of the 20th century were untreated hardwood. Although they were strong, they had a service life of between five and seven years. Exposure to the elements, insects, and fungal and microbial contamination meant that ties had to be replaced frequently.

In the early 1900s crosstie producers began treating the wood ties with creosote (also known as coal tar), a petroleum byproduct that provides a natural, biodegradable protective coating for the wood. Creosote extends crosstie service life to more than 20 years on average. However, the creosote penetrates the wood surface only a few millimeters, and once it wears off, the interior wood is again vulnerable to decay.

By the 1980s, researchers began testing other methods of treating wood ties to increase their useful life even further. One of the most effective additional treatments that has emerged is the use of diffusible borate preservatives.

Borates are broad-spectrum preservatives that protect wood from:

  • Termites and other pests
  • Moisture
  • Rot
  • Fungi

When applied by dip-diffusion or in a vacuum pressure process, borates penetrate through the entire crosstie, protecting the wood to the core. And when creosote is then applied to the surface, the dual protection extends the service life of the crosstie to more than 40 years on average.

That’s a dramatic extension. The result is:

  • Lower annual track maintenance costs
  • Greater safety over crossties that suffer less deterioration
  • Greater sustainability as fewer new-wood resources are required to meet maintenance demands

Reliable resource: Borate wood protection from U.S. Borax

Just as railway companies count on the reliability of their crosstie producers, those producers count on the reliability and consistency of the borates they use to protect and preserve their ties.

20 Mule Team® Tim-bor® delivers effective wood protection in a proven, reliably consistent and high-quality product. Crosstie producers depend on Tim-bor to ensure their formulations—and their end products—meet the standards required for the heavy duty they will face.

And, those producers depend on the reliable partnership of U.S. Borax. From knowledgeable customer service representatives to world-class logistics experts to a stable supply chain, U.S. Borax delivers the ROI that railroad crosstie producers need.

The story of rail transport is far from over. U.S. Borax is proud to help it continue.




U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

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