No Brahmaputra Mail have SM at DLI,as the distance is 2k+ km.And it can be also be given 130 clearance in NCR.There are some trains which doesn't get 130 clearance in NCR like Magadh(due to normal TT),Ganga Damodar in ECR(in order to avoid reach before timing in stations,not sent to GM for sanctioning of speed),Shram Shakti expres(due to overnight TT and TT for 110 speeding up is not possible).There are several reasons for a train to go 130 like availability of HS drivers, GM sanction for that train, 130 TT implementation, in order to avoid before timing for short distance trains.But I don't know the reason of Brahmaputra Mail not doing 130.