The transmission-line-matrix (TLM) numerical time-domain method using the symmetrical super-condensed node (SSCN) is applied to calculate the cross-talk time & frequency-response between tracks on a double-sided Vertical-PCB-on-backplane configuration over a frequency range of 50 MHz to 1 GHz. Meshing was done on a layer-wise basis which consisted of dividing the entire computational region into groups-of-vertical-layers in the XY plane, with each group of layers having the same mesh pattern. Extensive use was made of a recently introduced one and two dimensional multi-gridding technique to keep the total mesh count to a reasonable value. Perfectly-matched-layer absorbing boundary conditions were used and simulation was done for six PCB configurations for 100,000 time-steps, the time-step being 0.523 ps for a spatial resolution of 0.3175 mm. Simulation results compare well with the experimental data over the frequency range of interest.