As part of the Association of American Railroads’ (AAR) Strategic Research Initiatives Program, laboratory testing by MxV Rail (formerly TTCI) has evaluated how well different tie plugging materials could hold cut spikes in wood ties. The evaluated five tie plugging materials included wood plugs, three liquid-based synthetic materials, and one powder-based compound. Results showed that both the liquid- and powder-based materials met the test recommendations and had similar or higher extraction forces than those of wood plugs. Three wood ties were selected and tested to make sure the spike extraction forces on these ties were similar. To simulate the degraded condition, all tested spike holes were prepared to be a square hole with 3/4-inch in side length (larger than the nominal side length of a cut spike). The tie plugging materials were applied in both dry and wet conditions. The wet condition was achieved by filling the spike holes with…