I believe the short section between Badnera and the bifurcation point of the line to New Amravati was rewired when the Narkher route was getting electrified. Some old videos show the single wire OHE running all the way from Badnera to Amravati.
Even for pure passenger traffic, the speed may be restricted for longer rakes as they require more power from the OHE and consequently, the poor contact at higher speeds causes more problems.