It is called the fifth generation' s elevator internationally, two tracks of cars are located on two sides of the cars. Stresses of cars' two sides are balanced, hence there is nealy no noise of tracks' friction. It is more stable during operation. You will feel perfectly comfortable. In addition, the life length of the elevator is longer.
Characteristics of car frame type structure:
Because two rails are located on both sides of the car, it is like two people lifting a sedan. The force on both sides of the car is even and the operation is more stable, which is beneficial to extend the service life of the elevator.