Train doors at front DT car A3 door werenot proven closed. TC recycled train doors a few times but to no avail. Staff(KRJ) assisted to push close and isolate t he defective train door in close position at ADM2. ~~~~~ 3609 Train doors at front DT(3609) car A3 door were not proven closed. TC recycled train doors a few times but to no avail. Staff(KRJ) assisted to push close and isolate the defective train door in close position at ADM2.  (Level 3) L3 Fault cide 063 A3 CLEX2, Check and found A3 LHS outer door roller delamination, C/O ok. Matting strip, Push/pull, DLS red line, DCS, Door function and Door static test ok Done by Sanip/Jack 45117