TC reported smoke external at car 1563.SM(BSH) checked and confirmed BSH platform no abnormality. T rain 206 line cleared from BDL NB to BSH NB no abnormality. TC reported smoke external at car 1563. SM(BSH) checked and ~~~~~ TC reported smoke external at car 1563.     Check the above mention reported FC-721,Replaced external smoke detector done.Security check and function test ok. #1563-Smoke detector:- Not: 2485077 raise.    Done by Saini.  03/05/23