Mahlon Pitney, Southern Railway Company v. Crockett…
“ Indeed, it is not seriously disputed that there exists as much reason for having the drawbars of the locomotive adjusted to a standard of height as exists in the case of freight cars.The experience of the Interstate Commerce Commission, in seeing to the enforcement of the act of 1893, tended to emphasize the importance of interchangeable equipment upon the rolling stock of railroads engaged in interstate commerce, so that cars used in such commerce would readily couple with cars not so used, and that locomotives could be readily coupled with cars of either sort. ”
