No question of preference here. Mangala entered the block section first and thus it was allowed to proceed...:) Nowadays whenever 12432 is on time, it waits for 12134 at Senapura or Bijoor because of the long block sections in between Kundapur-Senapur-Bijoor...:) Similarly, the Rajdhani often waits for 12630 at Barkur because of the long block section which is occupied by 12620 prior to 12432.