Wedevelopandbuildanewtypeofinspectioncar.Abeamthatisnotrigidlyconnectedtothetrainaxleboxesandcanabsorbthevibrationandimpactcausedbythehighspeedtrainisused,andalaser-camerameasurementsystembasedonthemachinevisionmethodisadopted.Thismethodprojectsstructurallightontothetrackandmeasuresgaugeandlongitudinalirregularity.Themeasurementprincipleandmodelarediscussed.Throughnumerouspracticalexperiments,therebuiltcarisfoundtoc