Mississippi State develops treatment to extend life of railroad ties

In 1985, a young and energetic Mississippi State University forest products professor began testing a new treatment on railroad crossties, the Starkville, Miss., Daily News reports. At the time, Terry Amburgey had little notion that his experiment would change railroad infrastructure almost 25 years later.

Amburgey, along with U.S.
Forest Service colleague Lonnie Williams, thought that treating railroad
crossties with borates and creosote would extend their service life. Borates
are chemicals used as both an insecticide and fungicide, and creosote is an
oily liquid often used for wood preservation. They also hypothesized that
borate treatment of non-seasoned ties would protect them from fungi and insects
while they were air-drying.

While creosote treatment
has been used on the nation’s railroad infrastructure for more than 100 years,
most wood species, especially white oaks and hickories, were not completely
protected by the oily, tar-like substance.

"Some wood species, such as
black gum, are completely penetrated by creosote and can be in service for
almost 50 years. Ties made of white oak and other hard-to-treat species were
failing after as few as seven years in high-hazard regions such as the
Southeast," Amburgey said. "These failures were primarily from decay fungi and
iron corrosion of spikes, which caused the wooden beam to weaken."

With more than 140,000
miles of railroad track and 3,000 ties per mile, changing ties every seven
years was expensive, Amburgey said.

"At the time of the initial
study, treating ties that were already in service to extend their life was
about $5 per tie, per year," Amburgey said. "The cost for replacing ties was
much higher."

After preliminary tests on
the MSU campus, double-treated ties were placed on a stretch of track in
Cordele, Ga., where severe decay was a problem.

"We knew that the borates
would penetrate and protect the interior against wood-destroying organisms,
such as decay and termites, and protect spikes from corrosion. We also knew the
traditional creosote would weatherproof the outer portion of the wood,"
Amburgey said. "However, we had no idea that after 23 years, the double-treated
method would protect the wood to such a degree that the ties remain in perfect
condition today."

Amburgey said the borates
move to the areas of the tie with the most moisture, keeping decay fungi out.
Additionally, the creosote coating keeps the borate from leaving the wood.
Norfolk Southern adopted the dual-treatment standard in 2005 for use in high-hazard
regions.

"The dual-treatment system
is saving us money and extending the natural resource by providing
significantly greater tie life," said Jeff McCracken, assistant vice president
for maintenance of way and structures for Norfolk Southern. "We also are
experimenting with using less creosote retention in the dual-treated ties to
not only extend the creosote in times of shortage, but also find savings as we
determine the best combination of borates and creosote."

Norfolk Southern is not the
only company to adopt the technology. Some 25 years after the research idea was
conceived, nearly a million ties are dual-treated and installed annually by
Class 1 railroads, a classification given to the largest revenue-producing
railroads in North America.

Amburgey retired in 2009
after 30 years of service, but his vision for long-lasting railroad ties is
still being pursued at the land-grant university. MSU Forest and Wildlife
Research Center assistant professor Shane Kitchens has continued the research
program, collaborating with Amburgey to develop supplemental treatments for
in-track wooden crossties.

"There are more than 400
million crossties in use, with an estimated 23 million replaced each year,"
Kitchens said. "The system developed by Amburgey and Williams will provide long
lives for railroad ties. Through education and demonstration, we hope to
increase the number of railroads using the system."

Norfolk Southern and the
Railway Tie Association recently demonstrated the advantage of the dual
borate-creosote treatment in Cordele, Ga. More than 50 railroad engineers,
purchasers and quality control staff were in attendance.

"When people see how well
the crosstie performs and looks, they are immediately sold on the concept,"
Kitchens said.

The technology to extend
the life of railroad crossties, which began at Mississippi State, is still on
the move.