TC reported train doors at rear M1 car not proven closed. TC opened and closed train doors to no ava il. SM (KTB) assisted to push B2 door for train to depart. ~~~~~ Check no FOD. Found both roller damage and rusty. Replace roller ok, push/pull resistance ok. Checked no sign of leak. J-rail and door guide clean up ok. Weather strip check ok. Door cyclic test 20x ok. Door speed check within criteria. 10/20mm door gauge test pass. Done by Sanip/Koh. 20/02/21.