中文摘要：

首先比较了国内轨道不平顺统计谱与国外轨道标准谱的差异．根据沪昆和金温两条线路的轨道不平顺检测数据，利用Matlab编程计算功率谱（PSI））和轨道质量指数（TQI），结果表明，沪昆线路轨道不平顺功率谱要明显好于美国六级铁路的不平顺谱，而金温线轨道谱接近于美国五级铁路的不平顺谱．利用相干函数对轨道不平顺与车体的垂向和横向振动加速度进行相干分析，并结合车体加速度功率谱分析，归纳出轨道不平顺不利波长的范围，为轨道的养护维修和管理提供了理论和实践指导．然后再对各项轨道不平顺谱值进行积分，得出TQI单项指数与各轨道不平顺谱面积值具有很好的相关性，从而验证了用功率谱评价轨道质量的可靠性．最后建议将轨道不平顺功率谱作为控制提速线路轨道质量的主要指标之一．

英文摘要：

A comparative study was made of the China railway track irregularity statistic spectrums and foreign railway track irregularity spectrums. Then, based on the track geometry data collected from Shanghai-Kunming and Jinhua-Wenzhou railways,power spectral density（PSD） and track quality index （TQI） are calculated with Matlah program. The results show that the former track irregularity spectrum values are much smaller than those of the US class 6 railways, while the latter ones are close to those of the US class 5 railways. The coherence functions are utilized to analyze the relationship between track irregularities and vertical/lateral car body vibration accelerations. Together with car body vibration acceleration spectrum analysis, a conclusion is drawn about the range of detrimental track irregularity wavelengths, thus providing theoretical and practical guidance for track maintenance and management. Furthermore, the integral of each track irregularity spectrum values is calculated. The results show that each TQI has a close relationship with each track irregularity spectrum area. Consequently, it proves the reliability of appraising the track quality with PSI） analysis. Finally,the track irregularity spectrum is proposed to be one of the main indices to control the track geometry for speed-up railway.