TC reported that train doors in front M2car 'A4' doors were slow in closing. SM(BNL) checked and co nfirmed that the 'A4' doors in front M2 car were slow in clo sing. SM(JKN) assisted to isolate the defective pair of trai ~~~~~ Found 2636A4 door roller faulty. Replaced door roller and function checked ok. Operated doors 20x - ok, closing speed was normal. N.AKUMAR/09.01.22 --------------