To protect passengers,absorb enough kinetic energy and meet the special requirements for trains which are different from the other means of transportation,a method is presented to realize the plastic deformation threshold based on three main aspects of train connection structure,crashworthy vehicle structure,energy-absorbing component.In practical engineering,trains need enough strength and stiffness to transfer longitudinal force under the normal operation condition,and have to produce controllable large plastic deformation to absorb energy shortly under the collision condition.To realize the structural damage threshold of connecting structure in terminal end,two control methods are also proposed which can be divided as the parametric method based on ’extrusion’ and ’cutting’ theories;the method which can cut the connecting components between coupler-buffer devices and train bodies and separate them away when the damage thresholds of coupler-buffer devices are more than the pre-supposed damage thresholds.The damage thresholds can be realized based on changing the parameters of the number of shearing bolts,material parameters,etc.To realize the collision threshold of energy-absorbing components of trains,a control method is presented based on the ways of setting plastic deformation induced structure,local hole and pre-deformation structure.To realize the threshold of the controllable plastic structure of energy-absorbing vehicles,a control method is proposed for the multi-level longitudinal stiffness of train terminal structures. To protect passengers, absorb enough kinetic energy and meet the special requirements for trains which are different from the other means of transportation, a method is presented to realize the plastic deformation threshold based on three main aspects of train connection structure, crashworthy vehicle structure, energy -absorbing component.In practical engineering, trains need enough strength and stiffness to transfer longitudinal force under the normal operation condition, and have to produce controllable large plastic deformation to absorb energy shortly under the collision condition.To realize the structural damage threshold of connecting structure in terminal end, two control methods are also proposed which can be divided as the parametric method based on ’extrusion’ and ’cutting’ theories; the method which can cut the connecting components between coupler-buffer devices and train bodies and separate them away when the damage thresholds of coupler-buffer devices are more than the pre-suppos ed damage thresholds. The damage thresholds can be realized based on changing the parameters of the number of shearing bolts, material parameters, etc. To achieve the collision threshold of energy-absorbing components of trains, a control method is presented based on the ways of setting plastic deformation induced structure, local hole and pre-deformation structure. To realize the threshold of the controllable plastic structure of energy-absorbing vehicles, a control method is proposed for the multi-level longitudinal stiffness of train terminal structures.