The nonlinear propagation characteristic of the short-interval pulse trains in the anomalous dispersion regions of optical fibers was investigated numerically by adopting split-step Fourier algorithm for time intervals between two adjacent elementary pulses respectively being 1, 2, and 3, and number of elementary pulses being 9, 17, and 25. The results indicate that, although the pulse number, pulse position, pulse intensities, and the time interval between two adjacent pulses, may vary with distance, and although the weak pulse pedestal may extend to very wide temporal range during propagation, the whole main wavepacket all along maintains localized with their temporal duration being nearly unchanged instead of broadening obviously and rapidly. What is more, the main pulse wavepacket never repeats its previous profile, which means that the wavepacket evolution exhibits chaotic behavior. Thus, in this sense, the nonlinear evolution of short-interval pulse trains can cause the chaotic soliton wavepacket generation. Both the elementary pulse time interval and pulse number of the pulse trains affect the chaotic soliton wavepacket in terms of its sub-pulse number and especially its temporal duration.