RAILROAD employees in road passenger and road freight services have the option of receiving compensation upon a mileage or an hourly basis, and choose whichever gives them the higher wage for any particular trip. This arrangement rests upon the assumption that a certain number of miles run are the equivalent of a given number of hours of work. The assumed relationship between mileage and hours has not been changed during the post-war period; and, since basic conditions of train operation have changed, reductions in direct operating expenses per train mile are rendered difficult. In this article we intend to examine the equation of miles and hours and interpret its significance for railroad wage policy. data are reported each month to the Interstate Commerce Commission by Class I railroads in the United States. These figures have been summarized for all roads and, since July I92I, have been published monthly under the title, Wage Statistics of Class I Steam Railways in the United States.' Data are reported by occupational groups, of which fourteen are in train and engine service. These fourteen classes can be grouped into three main categories, road passenger service, through freight service, and local and way freight service; each of these includes the occupational divisions of engineers, firemen, conductors, and trainmen. The movements of the various series of reported data for the individual reporting divisions are similar within these broader classifications, and hence the process of grouping them is amply justified.