TIMS showed Fire Internal at car 3551. Staff(PNR) checked and confirmed no signs of smoke / fire / b urning smell on exterior or interior of train. Train was esc orted to terminal station. ~~~~~ * ,N * TIMS showed FC720 smoke internal occurred once on 3551. Fault could not be duplicated in depot. Checked fire control panel - no water ingress and wire security ok. Found smoke detecter dusty - blow clean with compressed air. Monitored - no fault occurence. DONE BY:SHARIF/SYAFIQ/SANKAR 18.08.2023