High-speed rail (HSR) is currently regarded as one of the most significant technological breakthroughs in passenger transportation developed in the second half of the twentieth century. According to the definition of the International Union of Railways (UIC), high-speed rail is a type of passenger rail transportation capable of operating at speeds of 200 km/h (124 mi/h) for upgraded track and 250 km/h (155 mi/h) or faster for new track. During the past 50 years, the high-speed rail has developed rapidly to meet the increasing demand for passenger rail travel. The development process can be divided into three stages.