By comparing the two, we will reveal the advantages and disadvantages of steel wheels and rails. First, we will compare the wheel with bipedal walking. The wheel is a multi-footed rotary body. It is demonstrated that the wheel can achieve higher speeds and consumes less energy. Next, we will compare the wheels of a railcar and an automobile. The wheels of a railcar are made of steel and run on the steel rails. As a result, a railcar can support a large load of over five tons in a small area of about 10 mm in diameter. The small ground contact area reduces resistance at high-speed running. Automobile tires have high running resistance because the rubber repeatedly contracts and recovers with each rotation. Despite these many advantages, the railcar wheel has one major weakness. It cannot climb steep hills. Also, it is slippery, like driving a car on snowy roads, and it is challenging to control the motor and brakes. The increase in the speed of railways has been a battle against this slippery nature.