TIMS showed Smoke Internal at rear M1 car. Staff(KTB) checked and confirmed no signs of smoke or int erior of train. Train was escorted to terminal station. ~~~~~ [ADDL] 1526 Smoke Internal. Staff(KTB) checked and confirmed no signs of smoke or interior of train. Train was escorted to terminal station.  1526 Fault code 720x1 time. Check smoke detector unit ono sign of water ingress, only dust.Air compress blow smoke detector unit,replace smoke detector head and function check ok.SDR1 already install, To monitor smoke detector unit(Only smoke detector head replace)    s/n:na Notif:2511256 Done by Zulq/Haslan 45139