I think I have a theory/hypothesis for the large amount of cockroaches present in this train. Yesterday, when I was travelling in AC 3A, a family in a bay next to me, made the lower berth their dining table. Spills and wastage WERE NOT cleared but shoved to floor. Train travelling during day time from MAS to CBE, has all its berths converted to dinner tables by passengers.
Of course, the counter theory, "rake maintenance should be done" is there. But with the amount of passengers travelling (TWICE than the ideal strength because of UR passengers), food waste could be higher hence attracting more pests.