Train doors at rear DT car 'B3' door notproven closed. TC opened and close train doors once - ok. T rain doors at rear DT car 'B2' door not proven closed. TC op ened and close train doors once - ok. ~~~~~ 3644 - B3 doors not proven closed. TC opened and close train doors once - ok. Train doors at rear DT car 'B2' door not proven closed. TC opened and close train doors once - ok.  3644 ER D/L - Done. Found B3 door having 'Closing Operation Timeout'. Checked J-rail & found no FOD. Door resistance test done on B3 door (Before 7.5kgf for both door leaf, After cleaning, LHS 5kgf RHS 5.2kgf). Door function check & Dt check - OK.  Au TK 44081