The ground-contacting surface of the railcar wheels exerts a longitudinal force to move forward and stop, as well as a lateral force, which is the leading player in the ‘turning’ process. The same forces are at work in the case of automobile tires, so we will start with an explanation of the familiar automobile tire. In the case of railway wheels and flanges on the wheel, the story is more complicated than that of the tire. The bogie is composed of two wheelsets. How the bogie can go around a curve without a steering wheel is explained pictorially. In the railcars, at high speed, ‘hunting’ occurs, a dangerous phenomenon that makes the ride uncomfortable and can lead to derailment. This countermeasure must be implemented while overcoming the conflicting issue of smooth curve running measures. This chapter introduces not only the mechanisms that enable the railcars to pass through curves and prevent hunting but also trackside innovations that allow smooth running around curves, and tilting and steering railcars that are good at running on curves.