Field validation of polyurethane technology in remediating rail substructure and enhancing rail freight capacity.

PDFTech ReportCFIRE 09-14RailroadsAir voidsSubstructuresFreight trainsRailroad tracksInjection (Geology)BondingField testsUnited StatesNational Center for Freight and Infrastructure Research and Education (U.S.)National Center for Freight and Infrastructure Research and Education (U.S.)US Transportation CollectionRailways are an important component of a multi-modal freight transport network. The structural integrity of rail substructure and problematic railway elements can be compromised leading to track instability and ultimately, train derailments. Because of this serious consequence, costly maintenance activities are routinely performed by railroads. An application of polyurethane void filling and particle bonding technology has been shown in the laboratory to mitigate impacts of ballast fouling and rail substructure deterioration and to enhance rail freight capacity. This study demonstrates its applicability and effectiveness in remediating rail substructure in the field. This study showed that polyurethane injection technology reduced settlements and increased track modulus significantly (i.e., at least onefold). A life cycle cost analysis was conducted considering a period of over a ten-years. Polyurethane injection technology appears to be a superior improvement methodology to traditional maintenance resulting in a cost savings from $1000 - $20,000 depending on discount rate. In the life-cycle analysis, polyurethane injection technology results in reduced use of water and CO2 emissions i.e., 90% and 10% of traditional maintenance, respectively; however, it uses 25% more energy