Transition curves are considered as inevitable parts of railways. As they tend to bend the train’s course of movement, the passengers ride comfort and safety are strongly challenged. Although many investigations have performed on the dynamic behavior characteristics of transition curves, only a few studies have focused on the optimum transition length based on the ride comfort index. In response to this need, a vehicle-track dynamic model was developed. The results obtained from model were compared with those available in the literature to prove the validity of the model. Through a parametric study, the dynamic responses of a vehicle passing through the transition curves was studied using the model developed in this study. The ride comfort index was obtained using the dynamic response of the vehicle. The lateral jerk, vertical acceleration, and rolling velocity were considered as the dynamic response of the vehicle. The optimum transition curve length for various configurations of curve radius and super-elevation magnitudes were investigated based on the obtained ride comfort.