SDI Subsidiary Ships First Composite Railroad Crossties to BNSF
04/15/2009 - Dynamic Composites ships its first production order of "green" composite railroad ties, which feature a flat rolled steel core filled with concrete and encapsulated by a tough skin made from recycled materials.
Dynamic Composites, LLC, has shipped its first production order of its "green" composite railroad ties to the BNSF Railway Co.
BNSF evaluated the ties, which are made from a variety of recycled materials, including steel, rubber, and plastics, before placing an order for 4000 ties. Dynamic Composites will ship nine railcar loads of the ties to Texas through April.
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Based on discussions with BNSF, Dynamic Composites recently developed a new tie design with a trapezoidal cross section that is wider at the base than at the top.
The new design helps to spread the weight of the train across a larger area of the ground below. The BNSF was looking for a better solution to this problem, which is especially an issue at the entry to tunnels, where it's important to preserve the integrity of the approach, rather than allowing the base supporting the tracks to be compacted.
The new design increases the surface area of the bottom of the tie by 10%, which helps to distribute the downward force across the larger supporting base.
"This is just one example of how our engineered products can be designed to meet specific performance requirements, as opposed to the traditional ties," explained Chuck Cadwell, General Manager of Dynamics Composites.
“In the new tunnel and bridge applications that we are exploring, the ties will require somewhat different configurations than the tie for general use, but we're confident we will be able to design and manufacture these products to meet the stringent performance requirements of our railroad customers.”
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The composite railroad tie begins with a core made of flat-rolled steel from SDI's Flat Roll Division. The core is filled with concrete then encapsulated by a tough skin made from a blend of shredded tires and recycled plastics. The tie benefits from all source materials, getting strength from the steel, mass from the concrete, and protection from moisture and the elements from the black covering, which is applied using an extrusion process. If spikes are to be driven into the tie, the core is filled with a special compound of recycled materials rather than concrete.
Dynamic Composites’ environmentally friendly composite ties offer a number of advantages over conventional creosote-treated wood ties, including superior vibration-dampening qualities and better load-bearing capability, resulting in a smoother ride and less wear on the railroad rolling stock. The composite ties are heavier, more solid and stronger, and also provide a longer life. The composite ties’ life, estimated at 60 years, could be 4 or more times the average life of a wood tie, depending on its application and environmental conditions.
Although the composite ties cost about twice as much as standard wood ties, its long life helps to offset the higher price, particularly considering the cost and downtime of replacing ties on a busy rail line. The composite tie shows a clear life-cycle cost advantage in hard-to-reach or hard-to-maintain applications, such as tunnels, trestles and bridges, wetlands, and areas prone to insect infestation.
"We look forward to continuing to work with the BNSF and other Class I railroads as we seek to expand our engineered composite-crosstie business," said Cadwell said. "Based on user feedback, we're already making improvements in our tie design, and we expect to continue to innovate."
Dynamic Composites, a majority owned subsidiary of Steel Dynamics, Inc., manufactures composite railroad ties at its plant near SDI's Structural and Rail mill at Columbia City, Ind.
BNSF Railway Co., a subsidiary of Burlington Northern Santa Fe Corp., operates one of the largest North American rail networks, with about 32,000 route miles in 28 states and two Canadian provinces.
