In this article we present a probabilistic spectral partition theory for a previously derived Monte Carlo method and show how to use it for the numerical simulation of Gaussian pulse propagation in a lossy transmission line with resistive boundary conditions. The spectral partition method consists in the random generation of frequencies, inside the source that feeds the line, and establishes the connection between the Monte Carlo line method and the tools of circuit analysis in the frequency domain. The main aspects regarding the implementation of this Monte Carlo algorithm are also addressed. © 2015 IEEE.