The long history of railway engineering provides many practical examples of dynamicrnproblems which are unique to railway vehicles. One of the railway vehicle's dynamicrnproblems is the lateral dynamic which is mainly arising from wheel rail contactrncondition. In the early time, to analyze and formulate such kinds of railway vehiclerndynamics scientists had been using different experimental methods such as roller rigsrnand roller coasters. Even though such experimental methods are most efficient andrnerror free, they are very costly and need some time. But now a day there are differentrncomputer packages used to study and simulate the dynamic behavior of a railwayrnvehicle (ADAMS/RAIL, SIMPAKC and Vampire). These computational packagesrnare very efficient in both cost and time but they are not more flexible and require indepthrnknowledgerntornrunrnthem.rnSornthisrnpaperrntriedrntornmakerntherncomputationalrntoolrnmorernrnflexiblernandrneasy tornusernwithrnbasicrncomputerrnknowledgern rn rnrnIn the work presented, mathematical model and computational tool used for therndynamic simulation of railway vehicle wheelset systems was developed usingrnmultibody systems formulations. The model based on the multibody techniquesrndeveloped by Shabana. With respect to other exciting methodologies the proposed onernmake use of a combined frame of references that permit the use of independent rncoordinates, without the possibility to have singularity configurations depending onrnthe rotation sequence. Lagrangian Equation of motions such as virtual work andrnkinetic and potential energy are used to develop the equation of motion. Finally arnMATLAB program is developed to analyze the dynamic behavior of the wheelset atrndifferent velocities on a straight track. The program was designed to considering thernflexibility of different configuration of railway vehicles. The model used was appliedrnto make a simulation for single wheelset. rnThe analysis were made for different velocities, lower than the critical in which thernvehicle responded in stable form, and higher than the critical at which the instabilityrnof the vehicle was studied. The obtained results of the dynamic response for a definedrntrack composed of tangent segment is analyzed and compared with one publishedrnpaper.