Only 1A and 1B platforms are Terminal Platforms at GAYA Junction.
PF 6, 7 are non-Terminal platforms
PF 6 nowadays is for 02364 RNC Patna Jan Shatabdi.
12398 Mahabodhi have also used PF 6....
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Palamu Express, Patna Bhabhua Intercity mostly use platform 6/7, (rarely PF 4/5)
07005 07007 07009 HYB-RXL SC-DBG SC-BJU have majorly used PF 6,7 (and PF 3 rarely).
09029 Surat-Gaya HS/ Bandra-Gaya Humsafar used PF 6/7