Train doors at front M1 car were not proven closed. TC recycle twice but to no avail. Staff(CCK) not iced a gap of 2 cm on front M1 A-3 door. Train was disembarkand DIRBS was operated. Train withdrawn and routed to UPD T  ~~~~~ 1516 Train doors at were not proven closed. L3 TC recycle twice but to no avail. Staff(CCK) noticed a gap of 2 cm on front M1 A-3 door. Train was disembark and DIRBS was operated. Train withdrawn and routed to UPD (L3) L3 1516 Found A3 LHS door leaf inner roller pitted badly. Pitted part drop on J-rail causing FOD gap of 2cm. Replaced with new roller & clean up J-rail. Door function test - OK.  Sugu/Anand/Lee PT/Kamarul 45260