They're basically replacing life-expired timber sleepers with low-profile single gauge concrete sleepers.
I'm not sure if they've been removing the light-weight rail. My understanding is that is a major impediment to raising the line speed. In the past year or so long sections between Bendigo and Elmore had 50 km/h TSRs on it. Only recently removed as far as I know.
The line now looks like 80 kph pretty much all the way to Elmore.
I looked the follow up video from Elmore to Echuca. There is a short section of 65kph as you leave Elmore, but it soon increases to 80kph. I saw some rail by the side of the track. Is that the old rail? Or some new rail waiting to be installed?
Given the long straight sections of the line, with very gentle curves, I cannot understand why they are not traveling at 120 - 130 KPH already.