OCTOBER 8, 2008
Recycling Materials for Sustainable Transit
By Leah Harnack, Associate Editor
Increased costs and the quest for more sustainable products have led to industry-changed products and services, including the use of composite ties. TieTek LLC makes ties that are a high-performance, long-lasting composite crossties with an estimated lifespan of more than 40 years.
The ties are 85 percent recycled material. Each mile of composite ties uses approximately 2 million plastic bottles, 9 million plastic bags and 10,000 scrap vehicle tires.
The ties afford a variety of benefits, including reduction of noise and vibration, better lateral stability than wood ties, abrasion resistance, low electrical conductivity and longer life-cycle over wood ties. The composite weighs three times less than concrete ties, with all of their associated fastening devices. Due to their weight, concrete ties are more costly to ship, handle and install, requiring more expensive and more extensive installation equipment. The TieTek composite ties do not require insulators or abrasion-resistant pads.
Those benefits are what led Chicago Transit Authority (CTA) to use composite ties. Christopher Bushell, director of power and way at CTA, stressed the greater durability and less maintenance as two of the reasons for using plastic ties.
CTA first installed plastic ties in the mid-90s on its Congress Line, with its first major installation on the Douglas Line around early 2001. “I would say that it’s become our standard for ballasted track,” Bushell said. He also said there is between 35 and 40 miles of composite ties in use.
The ties install like wood, are extremely strong, and are impervious to weather, moisture and harsh environments. They are resistant to wear, and are unaffected by fungi and insect damage. The ties are not susceptible to plate cutting or decay and they hold spikes and screws very well, so they maintain gauge on both straight and curved track over millions of gross tons of load, increasing track reliability and safety.
Bushell mentioned that over the years, CTA has used plastic and composite ties from different sources and that the products have improved over the years to make them even better. “TieTek is certainly the one we see the most of right now,” he said. “The ones now are the best quality ones we’ve installed.” When asked about the difference, he stated, “The more recent ties are more dense and more uniform.”
SOURCE: Mass Transit Magazine, Expo Daily
10/08/2008 |
