This paper compares two different methods to obtain rational approximations for the Universal Line Model (ULM) formulation. These approximations allow the representation of frequency-dependent transmission lines in the time-domain. The two fitting methods evaluated in this work are the pole relocation algorithm, known as Vector Fitting (VF), and the Frequency Partitioned Fitting (FpF). Both methods have their fit result of the admittance matrix and the propagation matrix in frequency-domain compared. The time-domain results for both approximations are obtained by simulating a field test in an actual 500 kV double-circuit transmission line in Japan. The simulations were ran on PSCAD and XTAP software packages which use, respectively, VF and FpF. The fit results in the frequency-domain shows that the two approximations are similar and present small relative errors, all of them in an order of magnitude of 0.1 %. Similar results were obtained for time-domain results, where both methods obtain similar representations and the simulation results are very close. Simulation results are also compared with measurement data of the field test. Although some differences are observed between simulations and the measured data, their general behavior are close.