This reminds me so much of a model railroad under construction: Track with no ballast, thin wooden shims under the track to level it and shiny rail ends where they've been cut off. The gandy dancers laying the "snap track" (another model railroad reference!) can be seen in the background, behind UP 4014. In about an hour, they will be satisfied with their work, and the big 4-8-8-4 will be towed backward again at a slow pace until it is safely positioned on the northern end of the track, at which point the process begins again: The track sections at the south end are removed and relocated to the north end, and then the engine it towed backward once again.
