Research conclusions:Themethod fordetermining the thickness of compressed layer is put forward throughmaking the analyses ofadvantages and disadvantagesof the allmethods in details. Based on the analysisof the load characteristicsof track, train and transporting girder vehicle and subgrade control factor of stabilization and settlemen,t the proposals are made to simplifying the load forms of track, train and transporting girder vehicle. Through the research on the different load transfer characteristics of foundation forms and formation conditions of composite foundation, it is pointed out the subgrade settlement control on passengerdedicated railway line should be conducted according to the cushion form of the embankmentbase and strengthening pile typeswith the composite foundation theory.