This paper introduces the RAPID intermodal transport system, an innovative solution that integrates passenger and freight transport using advanced Container Transfer System (CTS) technology. In response to European Commission targets for reducing road freight emissions and alleviating congestion, the RAPID system provides a sustainable, door-to-door transport alternative by enabling rapid, crane-free, vertical container transfers between truck trailers and rail wagons. This study addresses two primary research questions: (i) The feasibility of a CTS-based intermodal transport system for seamless door-to-door mobility, and (ii) its impact on transport efficiency, CO₂ emissions reduction, and economic viability in interregional transportation. To evaluate these aspects, we provide theoretical foundations for throughput analysis of such a system and develop and validate an optimization-simulation framework to match fluctuating demand under real-world conditions. A Danish case study indicates that the RAPID system can achieve a 94% reduction in freight CO₂ emissions and an 83% reduction in passenger transport emissions, improving capacity utilization and lowering operational costs. The results demonstrate that the RAPID system is a scalable, low-carbon alternative to conventional transport, capable of addressing modern logistics challenges. Future research will focus on pilot implementations, detailed economic assessments, and integration of emerging technologies to further enhance system performance and scalability.