The floating slab track system is a crucial element in urban rail transit, significantly influencing the structural health of the rail infrastructure. This paper presents a numerical investigation of the vibration response of floating slab steel spring isolators under failure and unloading conditions. Scenarios of single, consecutive two, and three-isolator failure, as well as unloading, are considered. Time-domain and frequency-domain analyses are performed on vibration acceleration, displacement, power spectral density, and 1/3 octave band levels at designated measurement points. The results demonstrate that isolator failure and unloading notably alter the vibration response of the floating slab, particularly in specific frequency ranges where changes in vibration acceleration are most pronounced. In the time domain, isolator failure and unloading have a limited effect on vertical acceleration but significantly influence vertical displacement. In the frequency domain, as the number of failed and unloaded isolators increases, there is a marked rise in power spectral density and 1/3 octave band levels of vertical vibration acceleration.