In recent years virtual dynamic system simulation has become very important in the design and development stage, as new strategies can be examined without expensive measurements and with reduced time. This paper describes the development of a simulation model for transient analysis of the longitudinal dynamics of a heavy tracked vehicle. The driving inputs for this simulation model are obtained from a powertrain model. The main elements of the powertrain include the engine, Torque Converter (TC), transmission and drivetrain. Here the engine is modeled based on the engine maps from steady-state experiments. The TC is modeled based on its characteristic map from experiments. A fairly simple transmission model is used which is based on static gear ratios assuming small shift times. The final drivetrain model however includes the rotational dynamics of the sprocket. The simulation model developed is validated by comparing the predicted values with the measured data from experiments. The results have demonstrated that the developed model is able to predict fairly accurately the acceleration and braking performance of the heavy tracked vehicle on both soft and hard terrain. © 2011 ISTVS. Published by Elsevier Ltd. All rights reserved.