Train doors at front DT car 'A3' door were not proven closed. TC recycled train doors twice- ok. Fault recurred at BGB NB for front DT car 'A3' door. TC recycle d twice to clear fault. At BBT NB & JUR MT, staff assisted t ~~~~~ Train doors at front DT car 'A3' door we     Check and found #3610-A3 LHS door main roller torn and worn off and cause door resistance very stiff.Roller replace done.Push/pull 5.5~5.6kg,Mating check ok.DLS,DLD and DSS (14.5mm)check ok.Door static and cycle test ok.Both side DIRBS seal ok. Done by Koh/Rizman. 05/05/22