Burlington Northern Sante Fe (BNSF) Railway is one of North America’s leading freight transportation companies and has over 32,500 route miles in 28 states. Dating back more than 160 years ago to 1849, the railroad began with a 12-mile stretch of railroad in Illinois. Over the next several decades, many additional rail lines were built and eventually became part of what we know today as the BNSF Railway. In 1994, Atchison, Topeka and Santa Fe (ATSF) Railway, which eventually merged to become BNSF, was building an impressive intermodal facility in Roanoke, Texas. They required the installation of a storm sewer culvert constructed just under the rail. They selected one of the most hydraulically efficient storm sewer systems available – ALT2 ULTRA FLO®, commonly known as Aluminized Type 2 Spiral Rib Pipe, along with some an additional helically corrugated culvert pipe manufactured by Contech Engineered Solutions. The system included 18” to 60” diameter pipes and often involved multiple barrel systems and crossings. Due to its unique corrugation and smooth interior surface, ULTRA FLO provides a Manning’s “n” of 0.012 and is ideal for storm sewer applications. The original construction involved approximately 13 rail lines in this large intermodal facility and switching yard. The ULTRA FLO and aluminized culvert pipe are running underneath the tracks and heavy intermodal container handling equipment which transfers containers on and off the container well cars. The pipes were backfilled with compacted sand and crushed stone.
As part of an in-ground performance study of aluminized type 2 (ALT2) steel, engineers from Contech revisited the site to assess the condition and performance of the systems after 20 years of service. Upon a visual and core sample inspection of the storm sewer and culvert systems, they found that the system was excellent structural condition, the shape of the pipe was as round as the day it was installed and despite significant bed load, the ALT2 coating was performing extremely well with no indication of erosion or material degradation in the invert. The enhanced abrasion resistance and durability of ALT2 ULTRA FLO® is meeting expected service life requirements and giving every indication of exceeding a 75-year service life. A steel coupon was obtained from the invert, or 6 o'clock position of the pipe, and analyzed providing another occasion in which ALT2 ULTRA FLO has outperformed and out-serviced other similar alternatives.
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