ATLANTA — Chicago has purchased 250 plastic railroad ties for its elevated rail line, according to a plastic lumber expert at Antec '98.
Thomas Nosker, a professor at Rutgers University in Piscataway, N.J., said the news from Chicago shows plastic crossties have gone from initial testing to actual commercial sales in three years.
``People are buying the ties now,'' Nosker said during a technical recycling session April 29 at the Atlanta conference.
US Plastic Lumber Corp. of Boca Raton, Fla., supplied the ties, which the company produces from recycled high density polyethylene and glass fibers oriented along the length of the tie.
Nosker outlined other milestones in railroad crossties made from recycled plastics:
In October 1995, 10 plastic ties were installed at the Rose rail yard in Altoona, Pa., intermingled with 20 wood crossties. The track is in a very wet area, where wood ties are prone to deterioration.
``The ties show no signs of weathering even though the winter of 1995-96 was particularly severe in the Northeast,'' he said.
In 1996 and 1997, ties were placed at the Pueblo, Colo., test track of the American Association for Railroads Transportation Technology Center. Trains continuously run around the track.
In October 1996, six ties were installed along Conrail's Pittsburgh-to-Philadelphia line, about halfway between the two cities. The crossties are located on a curved section of track where the speed limit is 35 miles per hour.
Nosker said plastic ties are the same size, and look the same, as traditional wood ties.
``The railroad guys feel comfortable if it looks like a tie,'' he said.
Crossties date to the early days of railroads, and are part of a total system — which includes rails, ties, connecting plates and rocks used as ballast — that distributes the weight of a passing train.
Rails must remain at the same gauge — 561/2 inches — and that gauge cannot change by more than one-eighth of an inch.
``Any more than that, it could be a risk of a derailment,'' he said.
Nosker said researchers found that smooth plastic ties need to be pre-dimpled so they sit better on the ballast.
Trains running on new wood ties have to run slower until the wood settles onto the ballast. But plastic ties properly treated with dimples could carry full-speed trains right away, Nosker said.
Makers of plastic-lumber railroad ties can make a profit if a tie can fetch a price of about $75, Nosker said. Creasote-treated wood ties cost $35 — and it costs another $35 to replace a wood tie the first time.
If they become widespread, plastic ties on U.S. tracks will be nothing like ties in Japan, where wood is scarce. The Japanese already use composite ties, made from virgin materials — foamed polyurethane with a continuous glass reinforcement. Those ties also help trains run quieter.
One of the tests in Colorado checks to see if the connecting plates indent into the tie — a problem with wood ties.
Norfolk Southern and the U.S. Army Corps of Engineers also are researching spikes for plastic ties, he said.