TC reported train doors at car 1617 didnot opened. Staff(SBW) checked and confirmed 'B4' train door s of car 1617 did not open. Staff(WDL) isolated the defectiv e train door in closed position. Train was a scheduled UPD w ~~~~~ 1617 TC reported train doors did not opened. Staff(SBW) confirmed 'B4' train doors did not open. Staff(WDL)isolated the defective train door in closed position.  Train was a scheduled UPD withdrawal train.  1617 B4 door FC 980/986. Checked/found door stuck on RHS & found RHS outer door rollerdamaged. Replaced the damaged RHS door roller & security check - OK.    Function check door open/close operation - OK. No FOD was detected & weather strip condition checked - OK. Cleaned J-rail/guide rail. Manually push/pull door & found no wobbling. Door gap = 64mm, door close s/w checked - OK. Door cyclic test 20x & DIR extinguished.  Rajamohan/Aiman/Aliff 45129