Train doors at front DT car were not proven closed. TC recycled train doors a few times but to no av ail. Staff(BGB) assisted to push close and isolate the defec tive 'A2' doors at car front DT car in close position at JUR ~~~~~ Train doors at front DT car were not pro     Check and observed A2 door closing intermittently stuck for few sec. then can fully close.Further check found left door roller wear mating strip was chip off-replaced roller ok.Door actuator and manifold check no sign of air leak.J and bottom guid rail clean ok.Door cyclic ok. 10/20mm door gauge test pass.Door static test pass. Done by Sanip/Koh. 28/02/22