Plastic Rail Ties Create Market for
An alternative to wood railroad ties, plastic ties, uses tons of plastic scrap. Plastic ties are being used in places like Chicago and New York City and in other railroads and transit systems.
Polywood, Inc. has created a plastic tie that uses all plastic scrap. Owner Jim Kerstein explained that the ties consist of high-density polyurethane and styrene.
"We have several patents on our ties. This is an immiscible blend, which means the two plastics co-exist without mixing. Basically we create fibers that give the tie strength. Our ties are all plastic. We don't have to mess around with gypsum, fiberglass or rubber."
The ties are principally composed of HDPE (milk jugs or juice container).
"We've also created a market for the styrene products, such as Styrofoam cups and lunch trays. The styrene didn't have much of a market before," he said.
Each railroad tie weighs and uses about 200 pounds of recyclable material.
Mr. Kerstein said, "A Styrofoam cup is about one-half ounce and a milk jug is just a couple of ounces. We are going through a lot of recycled products to put out a tie."
Railroads and transit systems are looking to the plastic ties as an alternative to wood ties. Wood ties are treated with a substance called creosote to protect them from the environment. This causes problems when it comes time to dispose of old worn out ties.
According to Mr. Kerstein the creosoted-outer layer of the wood either has to be cut off or the ties are often incinerated.
Ray Schriks, general manager Power and Way Engineering, Chicago Transit Authority said that creosote is now considered "special waste" and can't be sent to landfills.
"There are now disposal problems with creosote, which is why we started to look at using plastic ties. The future of disposal cost is hard to predict but it is a growing cost. We don't know where it will be 20 years from now," Mr. Schriks said. "With the plastic ties, we will be able to recycle them at the end of their useful life."
In 1998 the Chicago Transit Authority started testing plastic ties. The first ties were from US Plastic Lumber Company (USPL). Their ties are made with plastic and fiberglass. With the successful testing of these ties, the Chicago Transit Authority decided to extend the use of plastic ties and now purchases ties from four different companies including one in Texas, New York, USPL in Ohio and Polywood. Some of the ties are a rubber and plastic mix also.
Mr. Schriks said, "Our workers like the plastic lumber because it doesn't have the creosote oil. We placed sub-stantial orders from four different companies. All our new orders have been plastic ties."
On average, the Chicago Transit replaces 15,000 ties each year.
Polywood ties weigh 200 pounds, about the same weight of a wood tie.
Mr. Kerstein said, "This is an improvement over the other alternative tie, concrete. The concrete ties can weigh up to 800 pounds and require special equipment to install the ties. Ours are interchangeable with wood ties."
Polywood says its plastic ties will last 50 years. The average life of a wood tie is 20 to 25 years. Mr. Kerstein said in some areas a wood tie may last only three to five years, depending on the weather, moisture and insect infestation.
Mr. Schriks said, "Of course we'll have to see how these ties last, but if we can even get 30 to 40 years out of a tie, it will be worth it. (Currently plastic ties average about $25 more per piece than wood ties.) A lot of our lines are on expressways. These plastic ties seem to be more resistant to road salt and electrical corrosion. The plastic ties have low moisture content. These seem to protect our steel fasteners better from this type of corrosion."
Mr. Schriks said he also likes the plastic ties because they can be created with a dimple pattern. This pattern creates friction between the tie and the ballast and actually holds the track in place better."
Mr. Kerstein decided to look at manufacturing railroad ties as a way to use more plastic scrap.
"I've been in the plastics industry for years. I wanted to find a new product that could be made from recycled material. I wanted to do something so these materials didn't go to landfills. This is such an exciting project. The huge quantity of raw materials that it takes to make a tie is exciting and is hard to pass up," he said.
"Billions of pounds of raw material are generated, so we won't run out," Mr. Kerstein added. "We are currently buying the material already ground or flaked. It is easier for our manufacturing process than it would be to do our own mixing, collecting containers, washing and recycling the material ourselves."
He added that his company also manufacturers what many other plastic lumber companies do, decking, park benches, and picnic tables.
Currently over 30,000 Polywood ties are in use around the United States. The Polywood ties were first used in 1999. The product was developed in 1994 and is used in both tracks that lie along the ground and in elevated tracks such as in the New York City and Chicago transit systems.
"In the last couple of years, the acceptance level of the product has gone up and continues to go up," said Mr. Kerstein.
Mr. Schriks added, "These plastic ties are a good idea. I feel it's the right thing to do for the environment using the ties made from recycled plastic and not using trees. Right now 99 percent of the railroad ties in the US are still wood. I think the use of plastic ties is growing and once more people start using them the price will get better as production increases."