The statistics contained in this section cover all street and electric railways in the United States that were in operation during any part of the year ending June 30, 1902. The term "street and electric railways" as here used includes all electric railways irrespective of their length or location, and all street railways irrespective of their motive power. At the census of 1890 the railroads that used motive power other than steam were confined almost exclusively to urban districts and were properly classed as "street railways," but the application of electricity has enabled these roads to greatly extend their lines in rural districts, and a large proportion of the trackage is now outside the limits of cities, towns, or villages. That the use of electric power has been the principal factor in the development of these railways during the past few years is shown by the table which presents for the years 1890 and 1902, the number of companies and miles of single track in the United States, segregated according to character of motive power which is employed.