TIMS showed Smoke External Alarm at Front M1 car. Staff(YCK) checked and confirmed no signs of smoke/ fire / burning smell on exterior or interior of train. Re ar T231line clear and confirmed no abnormalities. ~~~~~ TIMS showed Smoke External Alarm at Fron   25/5 3559 smoke external, swap FCP to 1559. 20/6 1559 smoke external, changed out FCP (MO: 11709581) 11/7 1559 smoke external alarm Replaced External smoke detector unit and tested ok. Notification: 2505161