Passenger car
The nose shape was designed to reduce aerodynamic drag by 15% compared to the KTX-I. The carbody of intermediate cars is made of aluminum rather than mild steel, saving about 30% in weight. Passenger car width was increased from . The design was reviewed by Bombardier Talbot and DE-Consult from Germany and Alu-Swiss from Switzerland. For improved protection of passengers against air pressure variations during tunnel passages, the HSR-350x was equipped with an active passenger compartment pressure control system.