Chemical shipments on U.S. railroads jumped 26 percent last week, the Association of American Railroads said.

Chemical shipments on trains, called rail car loadings, are a measure of demand for products ranging from plastics to fertilizers.

For the week that ended April 10, chemical rail car loadings jumped to 29,467 from 23,380 a year earlier, the AAR said.

The figures often provide an early glimpse of broader trends for the chemical industry as well as manufacturing, according to analysts.

The weekly data indicated that year-to-date rail car chemical loadings had risen 14.3 percent from a year earlier.

Rail car loadings represent about 21 percent of chemical volumes by tonnage. Trucks, barges and pipelines carry the rest. (Reuters)