The indoor air of high-speed vehicle is automatically controlled by computer located inside the passenger car to make passengers feel optimal atmosphere. Through sensors, computer inside the passenger car can receive conditional information such as temperature and humidity of indoors and outdoors, and maintains the optimal indoor temperature and humidity automatically.
There is often inconvenience of feeling ear-ringing while taking a high-speed trains or airplanes. This phenomenon occurs due to by pressure-difference between indoors and outdoors of a passenger section, and in case of high-speed railroad, it happens during going through a tunnel or entering a tunnel. However, when the speed of the train is over 5km/h, high-speed train intercepts the outer air with the swollen rubber around the entrance with the command of computer in the passenger car. Especially, it automatically shuts down the ventilation system while going through a tunnel in order to prevent ear-ringing phenomena by restraining air changes inside the passenger car.
The reason general trains are so loud is because of the noise and vibration created by joints on the rail. High-speed rail does not have any joints, and therefore, there is much less noise and turbulance despite the far faster speed.
High-speed rails are made up of 300m long rails using special welding and are welded within every 300m to become sequel welded rail. General railroads are still composed of joint rails, but sequel welded rails replacement is now in progress.
Also, the wheels of high-speed vehicle are placed in between passenger cars and are not placed under the passenger car like general railroad vehicles, therefore reducing noises and turbulence. Another reason of reduced noise is using electricity and not the diesel engine as traction power .
