Stability analysis of railway vehicles and its verification through field test data

Dynamic stability is one of the important performance indices of railway vehicles. In the present paper, a twenty-eight-degree-of-freedom dynamic model is proposed to study the response and stability of railway vehicles. Nonlinear quantities existing in the railway vehicle system such as conicity, track irregularity and contact force between the wheel and rail are considered. Numerical simulation is performed based on a type of vehicle currently operated by Taipei Rapid Transit Corporation along with different kinds of track irregularity as random inputs. The stability of the vehicle is discussed in detail and compared with other full-scale test data available. It is found that the simulation result is in good agreement with the test data. Both of them indicate the transverse acceleration of the bogie meets the required stability criteria set by authorities for mass rapid transit vehicle systems. With regard to the car-body, when the vehicle is operated below the speed of 148 km/h, the lateral throw of the car-body is found to be below the required level. To avoid flange contact, the lateral excursion of the wheel-set is examined as well. It is found that flange-rail contact will not occur very frequently for the studied vehicle when operated at its regular service speeds. It is concluded that the dynamic model is appropriate for the stability study of a railway vehicle, and the dynamic performance of the studied transit vehicle is quite good.