The present disclosure relates to a transitional mode high speed rail system. The high speed rail infrastructure employed by the system is constructed adjacent a conventional host highway. The infrastructure can be provided adjacent to acceleration/deceleration lanes, or emergency parking/paved shoulder lanes. The vehicles used by the system are individual, self-powered, self-operating, individual mass passenger transport vehicles similar in size and appearance to municipal buses. These are transitional mode vehicles because they operate as railroad vehicles on the high speed rail infrastructure, but transition to automotive vehicle mode traveling on ordinary paved roads. They are mass passenger transport vehicles because many passengers can be accommodated.