Photo captioned, "Laying the rails of U.P.R.R.--Two miles a day." Photograph by Union Pacific Railroad's official photographer John Carbutt.

Building the transcontinental railroad transformed the art of laying rails into something of an exact science.  In time both roads were laying two, three, and even four miles day after day. For its part, the Union Pacific was resting on its laurels, having some months earlier staged a marathon from daybreak into the night that yielded an amazing seven-and-three-quarter miles.