That happens in very rare cases if the particular zone doesn't want that particular from their shed , for example WAP1 they would be interested to hand over it to different zone . For now SCOR has 2 divisions with Electric loco sheds VSKP and BZA so Guntakal division can depend on these divisions for loco's to be transferred to GTL shed . Maybe in the future SCR might hand over particular shed Loco's to GTL if they feel it ain't necessary to be used . Now in the case of SWR which is not having a single Electric loco shed , I heard KJM diesel shed will be homing Electric locomotives so there are high chances of SR Zone alloting E loco's to SWR as most of the SWR zone train's highly depend on SR based E loco's.