Cable scrapers whether towed or self-propelled took some finesse and always careful attention to cable and sheave condition and lubrication. Sheave nests were so difficult and expensive to repair. Replacing broken cable runs were not a job for the timid or faint of heart.
I had a fleet of these for a contractor in Illinois and wore out the phone looking for decent used and new parts. Same with the #25 cable control unit. Pete did himself a big favor by converting over to hydraulics, no matter the cost. At least he could then get parts.
Even as old as I am, I did not see many self propelled cable cans still running in the late 60’s, but strangely enough, there are still some in use today. One sees them occasionally here and there. I ran the model 70 and 80, also the 433 behind D8’s and D9D's, then there were the DW20, DW21’s and an old 631 cable rig that I got stuck on for a few days. I really don’t miss them.