Steel spring isolators are critical components installed beneath floating slabs in rail transit systems. Their damage can severely compromise train operational performance and safety, yet such damage often remains undetectable through conventional inspection methods due to its concealed nature. Traditional static sensor deployment approaches are unsuitable for long-distance inspection. A dynamic inspection monitoring system was developed and the influence of isolator damage on vehicle body vibration was analyzed in this study. A rail transit dynamic monitoring system was first established to collect measured dynamic response data from subway vehicles in operation. Subsequently, a vehicle-track coupled dynamics model was constructed using ABAQUS and SIMPACK software, and its accuracy was validated through comparison with measured data. To more realistically simulate subway track irregularity characteristics, a full-frequency track excitation spectrum was developed by combining the American Class 6 spectrum with the Sato short-wave spectrum, covering both medium-long wave and short-wave irregularities to enhance model precision. Based on this model, the damage factors affecting vehicle body vibration response were identified and calculated. Finally, a quantitative analysis was conducted on the influence of multiple damage factors on vehicle body vibration response. The results demonstrate that the dynamic monitoring system can be applied to long-distance isolator damage inspection in rail transit systems. Regarding ride comfort indices, damage severity was found to be the most significant factor with a weight of 52.2%. Damage location ranked second at 25.4%, with the most pronounced effect observed at floating slab junctions. The influence of damage quantity was relatively limited at 22.4%. For acceleration peak values, damage severity accounted for 46.6%, damage location for 33.9%, and damage quantity for 19.5%. These findings provide a basis for the identification and application of damage inspection systems for steel spring isolators in rail transit systems.