The feasibility of track-length distribution biasing for the calculation of spatial and angular particle flux far from the source in an infinite medium is investigated. Calculations are performed for an idealized particle transport model having an exact analytical solution, and results for scalar flux are given to a penetration distance of approximately 60 mean-free-paths. Results are also given for angular distributions. It is found that the “optimum” biasing parameter “a” for scalar flux prediction can be approximated by a exp(−a) = 0.368c n/40 (a revised form of an empirical expression from an earlier study), where c is the probability of scatter and n is the desired penetration distance. If appropriate corrections are made for the effects of inelastic and hydrogen scatter, the present results can provide useful guidance in the application of the track-length distribution biasing technique to more realistic systems.