With　its　high　infection　rate,　COVID-19　has　swept　the　globe　and　brought　great　challenges　to　social　life　and　economies.　As　an　essential　form　of　public　transportation,　the　Beijing　subway　plays　an　important　role　in　transportation　systems.　In　traditional　subway　organizations,　all　one-sided　doors　of　a　train　carriage　are　employed　for　passengers＇　alighting　and　boarding.　A　higher　risk　of　COVID-19　infections　may　be　attributed　to　inevitable　bidirectional　conflicts　at　doors　with　higher　passenger　volumes.　Moreover,　quantitative　analyses　for　this　problem　and　corresponding　solutions　are,　limited　in　recent　studies.　In　this　research,　conflicts　at　carriage　doors　are　analyzed　using　a　cellular　automaton　(CA)　based　model.　Four　schemes　to　separate　alighting　and　passenger　boarding　into　separate　doors　are　investigated.　The　performances　of　different　schemes　with　various　alighting　and　boarding　passenger　ratios　are　simulated　with　the　software　package　Legion　Studio.　Both　macroscopic　and　microscopic　parameters　to　characterize　passenger　conflicts　are　obtained　for　analysis.　The　separation　of　alighting　and　boarding　passenger　flows　yields　the　desired　reduction　in　bidirectional　conflicts,　which　further　limits　the　probability　of　infectious　disease　exposure.　This　is　an　important　reference　to　improve　current　practices　and　provide　specific　measurements　of　passenger　organization　under　abnormal　situations.　(c)　2021　Elsevier　B.V.　All　rights　reserved.