Railroads. Freight and passenger train service unit costs (selected expense accounts) of class 1 steam roads in United States, including proportion of mixed-train and special-train service (compiled from 161 reports representing 176 steam roads, switching and terminal companies not included), Aug. 1923 and 1922, and 8 months [ended with Aug.] 1923 and 1922; [prepared in] Bureau of Statistics.