TC reported obstacle detected at rear M1car 'A4' door. TC opened and closed train doors a few times to clear fault. Staff (CBR) feedback that the door was slow in closing. ~~~~~ TC reported obstacle detected at rear M1     Found both LHS/RHS saloon door roller faulty. Replaced roller,check and clean J-rail guide and no FOD found. Saloon door tested open & close several time ok. Door mating-Top=63.2,Centre=64.2,Bottom=63.3 Push/pull-LHS=7.5,LHS=7.5 DCS plate=14.5 Done by Saini/Koh/Haslan. 18/12/20