TC reported fire external alarm at frontM2 car. Rear T222 performed line clear and confirmed no sig ns of smoke or fire at trackside. Staff(AMK) checked and con firmed no signs of smoke or fire at front M2 car. ~~~~~ TC reported fire external alarm at front NL1   #2618 FC-721,Found #2618-#2 end smoke detector terminal having corosion.Replace smoke detectoe and function test ok. Done by Zul/Haslan/Saini  24/11/21