High-tech D&RGW rail retainer

While going through old slides I came across this one taken while walking the grade a couple miles west of Sublette back in August 1973. Having never seem anything like it before, it caught my eye and I decided to snap the shutter. It was on a curve, but obviously couldn’t replace a real, steel retainer. My guess is that it might be the track equivalent of doweling a screw in woodwork; the spike holes could no longer hold spikes, so instead of replacing the tie the section crew moved them outward with this hunk of wood. How often were things like this done in the old days?