Given the growing importance of developing passenger rail transport in modern economic and social conditions, increasing the passenger capacity of railway rolling stock is becoming a key objective. Enhancing the capacity of passenger wagons not only contributes to more efficient utilization of existing railway infrastructure but also allows for a reduction in the number of required trips. This, in turn, helps decrease operational and maintenance costs, thereby lowering the overall cost of transportation services for the population and improving their affordability and accessibility in the long term. The article provides a scientific rationale for increasing passenger capacity and presents the results of design and engineering work aimed at developing a new model of a long-base passenger wagon. This advanced modification is specifically intended for operation on the railway network of the Republic of Uzbekistan, taking into account the region’s unique climatic and operational conditions. Particular attention during the design process was given to ensuring the structural strength, stability, and safety of the wagon. The proposed solution is expected to improve the efficiency of rolling stock utilization, meet the growing demand for passenger transportation, and support the strategic modernization of the national railway infrastructure.