TC reported smoke external at Front DT car. Rear T409 line clear no sign of smoke. Staff(AMK) checke d no sign of smoke at Front DT car. ~~~~~ 3528 TC reported smoke external. Rear T409 line clear no sign of smoke. Staff(AMK) checked no sign of smoke at 3528 car. CE: 3528 found car having smoke external pre-alarm fault. No abnormality found. Reset, fault cleared.  3528 FC 721 registered once. Opr 20 raised To check plaseal and smoke detector. Akira 45035 To check plaseal and smoke detector