To　study　the　dynamic　response　law　of　the　ballast　track-subgrade　coupling　system　under　the　action　of　train　dynamic　load,　considering　the　real　shape　of　ballast　particles,　a　refined　discrete　element　model　of　the　rail-sleeperballast　bed-subgrade　coupling　system　was　established.　The　established　model　can　realistically　simulate　the　coupling　mechanism　between　irregular　ballast　particles,　between　track　panel　and　ballast　bed,　and　between　ballast　bed　and　subgrade　under　train　dynamic　load.　The　validity　of　the　established　model　is　verified　using　on-site　measurement　results.　This　study,　from　a　microscopic　perspective,　focuses　on　particle　contact　forces,　vibrations,　and　frictional　energy　consumption　in　the　rail-sleeper-ballast　bed-subgrade　coupling　system　under　train　dynamic　load　and　investigates　the　influence　of　train　speed　and　axle　weight.　Results　show　that　an　increase　in　train　speed　and　axle　weight　enhances　the　number　and　probability　distribution　of　strong　force　chains　between　ballast　particles,　increasing　the　risk　of　particle　breakage　and　deterioration.　The　influence　range　and　depth　in　the　ballast　bedsubgrade　system　increase　with　the　train　＇　s　speed　and　axle　weight.　Due　to　the　granular　nature　of　the　ballast　bed,　the　vibration　acceleration　distribution　of　ballast　particles　under　train　dynamic　loads　is　relatively　random.　Overall,　the　vibration　level　of　the　ballast　bed　increases　with　train　speed　and　axle　weight.　The　frictional　energy　consumption　of　ballast　particles　rapidly　grows　as　the　train　＇　s　bogie　load　passes,　and　the　effect　of　train　axle　weight　on　the　frictional　energy　consumption　of　ballast　particles　is　more　significant　than　the　train　＇　s　speed.