Train doors at rear DT car were not proven closed. TC recycled train doors once - ok. Fault did not recur at subsequent stations. ~~~~~ 3650 Train doors were not proven closed. TC recycled train doors once - ok. Fault did not recur at subsequent stations. CE:3650 all doors operation ok, proven closed. No DIR fault OE depot check  3650: Train door NOT PROVEN CLOSED. Download ER.Code 083 on 3650 A4 Door (CLE) (Fault trace show DOBS) Checked FOD on doorguide - OK. Weather strip check - OK. No external marking marks/sound. J-rail checked - OK. No dust particles. Cleaned up J-rail as preventive measure. Door resisitence test (6.8kg.) Door cyclic test - OK. Closing time/opening time within criteria. DIR Able to extinguish. Postulate FOD Dislodged. Au TK 44737