As US cities continue to accommodate more people and jobs, they have created increasing travel demands, especially on inter-city commute. Due to the spatial distance among cities and a long tradition of car-oriented lifestyle in the south, cars are the major mode for people traveling to different cities. With emerging papers and reports on building a regional framework for the US mega-region, a sustainable transportation network with various transport options has become a heated topic for state and local transportation agencies. Multiple National Household Travel Surveys (NHTS) have shown that private vehicles dominated intra- and inter-megaregion travel in the United States and such travel pattern will cause further congestion on regional highways and negatively impact passenger and commodity flows in mega-region. An efficient mobility supply for megaregions aims to achieve multi-modality that utilize different modes (automobile, rail, bus, and air) for mega-regional travel. This report utilizes the National Household Travel Survey and ACS commuting flow data to explore the travel patterns of Texans. A mode choice model from National Cooperative Rail Research Program (NCRRP) Report 4 was calibrated to investigate how mode share would change for travelers in the twin-megaregion area that includes the Texas Triangle and western Louisiana. The aggregated findings provide solutions for effective network performance, and the report further discusses the possibilities of modern railway service in the twin megaregion-area. This study starts two case studies where train transit can be effective solutions to transportation supply. Then it explores the traffic corridors in these two states with commuting survey and data. Last, trip generation and mode choice analysis confirm the abundance of rail riders in the future, and the report offers policy suggestions for policymakers to prepare for the potential changes