The bulletins of the census furnish, to some extent, the statistics relating to rapid transit in cities, and of the relative economy of different motive powers used on street railways. These bulletins have been prepared by Mr, Charles H. Cooley, special agent for rapid transit facilities in cities, under the immediate direction of that skillful statistician and economist, Mr. Henry C. Adams, special agent for transportation, and from them we learn the growth of rapid transit facilities during the ten years from 1880 to 1889, inclusive, in cities having over fifty thousand inhabitants. The special experts have selected cities on a basis of an estimate of population made at the time the compilation of the tables was begun.
The full reports of the statistics of the equipment of all roads furnishing rapid transit facilities, and of their operations for the single fiscal year ending 1890, are being collected, and the census authorities will present them in future exhibits.
Prof. Adams announces, and with truth, that street railways have never before been brought within the scope of the census statistics of transportation, and he points out the peculiar difficulties which were met with in collecting the facts already presented. Some of these difficulties arose from the ambiguity of designation, as "length of line," "length of single track," and "length of double track," when applied to street railways; and on account of such ambiguities the attempt has been made to fix upon some definite nomenclature by which careful returns can be secured. The conclusion is, that "length of line" means length of roadbed, or, in case of railways running entirely upon streets, the length of street occupied; that "length of single track" means the length of that portion of the road-bed or street laid with one track only; and that "length of double track" means the length of that portion of the road-bed or street laid with two tracks. In determining the total length of tracks, switches and sidings have been included, and thus double track has been reckoned as two tracks.
On December 31, 1889, 476 cities and towns in the United States possessed rapid transit facilities, the total number of railways in independent operation being 807. Many railroads, however (and the number is stated at 286, having a total length of 3,150·93 miles, and 13, having a total length of 135·75 miles), have as yet made no report; while in six the returns received were so imperfect that it was necessary to supplement them by approximations. This statement accounts for the bulletins not presenting statistics for a series of years for the whole number of railroads in the country, and m cities have been selected for which the reports are comparatively complete. Suburban lines tributary to large cities, but without their corporate limits, as well as
