The halt is for loco reversal & idle time negotiates TAT for loco movement from back to front, as it negotiates regular traffic to restore!!
Further, train which dont have loco reversal but change (Rewa SF, Swatantrata Sainani, Mumbai-HWH Mail etc) finish the entire process within 20-25 mins!!
PS: Train getting LC have same kinda idle timing @ DD where u will find every LC train idling not less than 40-45 mins!!