Abstract: Objective: Track shortwave irregularities can lead to highfrequency vibrations in wheelrail system, resulting in a significant wheelrail impact force and undermining operational safety. It is aimed to investigate the characteristics of urban rail transit track surface shortwave irregularities.Method: Based on the fieldmeasured data of Shanghai Rail Transit Line 11 track surface shortwave irregularities, the fieldmeasured data is preprocessed by eliminating outliers and trends. ISO 3095:2013 AcousticsRailway applicationsMeasurement of noise emitted by railbound vehicles is used to evaluate the track surface irregularities along Line 11 Zhenru Sta.Fengqiao Road Sta. interval. The maximum entropy spectrum method is employed to estimate the track shortwave irregularity power spectra for different track types. The obtained power spectral density curves are compared with the shortwave irregularity power spectra proposed by China Academy of Railway Sciences for ShiTai Line (ShijiazhuangTaiyuan) and the roughness power spectrum suggested by scholar Sato.Result & Conclusion: The amplitude distribution of track shortwave irregularities approximates a normal distribution, with the maximum track irregularity amplitude reaching 1.5 mm. The frequency distribution curve of track shortwave irregularities exhibits high in the middle and low on both sides, the characteristics of which resembles the normal distribution. Within the analyzed wavelength range, the horizontal spectral values of track shortwave irregularities exceed the limits specified in ISO 3095:2013, with a maximum difference of 20.87 dB. The DTⅢ2 fastenertype bearing block track structure exhibits better track surface irregularity conditions compared to the vibrationdamping fastenertype bearing block track structure and the floating slab track structure. The track surface condition of Shanghai Rail Transit Line 11 is better than that of ShiTai common speed railway line.