TIMS showed Smoke Internal at Reat DT car. Staff(BSH) checked and confirmed no signs of smoke / fire/ burning smell on exterior or interior of train. Train was escorted to terminal station. IMDC(RS) informed CE assisted  ~~~~~ TIMS showed Smoke Internal at Reat DT car (3539) . Staff(BSH) checked and confirmed no signs of smoke / fire / burning smell on exterior or interior of train. Train was escorted to terminal station. IMDC(RS) informed CE assisted  At mainline, 3539 smoke internal 1 was triggered. Chcked and found smoke sensor dusty. Used compress air to clean up the sensor and RAD area. Function tested smoke detector ok.    Done by: Koh/Rizman/Jack 45201