I am not sure about this, but I believe they might be antennas for DP(W)CS (Distributed Power control).
In normal MU units, the locos are connected by cables. When freights have banker locos, the bankers are controlled independently and the lead loco does not control the rear locos.
For such cases, IR developed a system for controlling all the trailing locos from the lead loco over a wireless link, called DPWCS.
I...
more... know that Raipur has some EMDs which have been fitted with the DPCS system. These things look like they might be the antennae for the wireless DPCS system.