Pax feedback to staff(EUN) that one of the train doors did not opened at car 1612. Staff(LVR) checke d and confirmed the 'B4' doors at car 1612 having abnormalit ies when opening. ~~~~~ #1612 B4 DOOR OPENING SLOW.CHECK AND CONFIRM FAULT AT LOCATION.FURTHER CHECK RHS SALOON DOOR MOST R/S ROLLER DAMAGED T5O PIECES.INNER R/S ROLLER CRACK.LHS SALOON DOOR MOST L/S ROLLER CRACK IN PROCESS OF DELAMI TION,INNER L/S ROLLER NOT SMOOTH.C/O 4 ROLLERS SECURE CHECK OK.CLEAN J RAIL OK.FUNCTION CHECK DOOR OPEN/CLOSE CYCLIC NTEST FOR 20 TIMES OK. VICTOR/SHAHRIE 21.06.2023