The U.S. Department of Transportation, John A. Volpe National Transportation Systems Center (Volpe Center) Cambridge, MA, is supporting Federal Railroad Administration (FRA), and has a requirement for the renewal of two licenses to operate NUCARS software. NUCARS is the only simulation package that has been sufficiently validated to predict the nonlinear dynamic response of North American Railroads to specified track conditions. It is also a proprietary software of Association of American Railroads (AAR) which is a requirement for rail dynamics studies. NUCARS software is required to access the results from decades of past simulation work performed by Volpe Center engineers. Therefore, The Volpe Center intends to award a sole source purchase order to Transportation Technology Center, Inc. DBA MxV Rail Software Products. The NAICS code for this procurement is 541519; the small business size standard is 30.0M.