ABSTRACT
The assessment of conditions of the railway substructures including the rail fasteners, ballast and foundation using the vehicle response will be studied in this paper. Finite element analysis is adopted with the rail modeled as an infinitely long beam on discrete springs. Since interaction forces exist at the wheel-rail contact points, the equations of motion of the vehicle and the track system are coupled, and it becomes possible to assess the conditions of the railway substructures by monitoring the vibration response of the vehicle. The vehicle moving on the rail track can be idealized as a series of lumped masses supported by the suspension systems (Yang & Yau, 1997). Only one half of the vehicle is taken into account for
1 INTRODUCTION
As a stiff wheel rolling on a rigid rail requires less energy than road transport, railroads are developed rapidly for the movement of dense, bulk goods such as coal and other minerals in the past. Nowadays, many countries have developed highspeed railroads to connect major cities, especially in China. The levelness of the railway track is an important factor to gauge the safety of the railway due to the high speed of the vehicle.
