It's rare but do happen as happened with TN & Kaifiyat!! It was not overtake as schedule wise AP has to run ahead which trailed coz of some technical reason in BPL-AGC!!
160 MPS track with clear 130 usual MPS for both Raj & AP makes AGC-NDLS run slacked & easily recoverable for few minutes delay!!
SBC Raj termination at NZM will create unusual block for AP & push it to reach NDLS at 6:00 which got avoided!!