TIMS showed train doors 'A3' at rear DTcar not proven closed. TC opened and closed train doors and PSDs a few times but to no avail. Staff (BDL) assisted to is olate the faulty train doors. However, DIR indication remain ~~~~~ #3635-A3 door found door isolation device was damaged. Replaced new device and do all function test-tested ok. Downloaded ER fault trace data - N . Done by Jack/Sateesh/Koh. 24/05/20. RS suspect foreign object was trapped and dislodged eventually.