Most people find relative velocity to be a relatively difficult concept.
In one dimension, however, it's reasonably straight-forward. Relative velocity in 2 dimensions Note that there's an interactive simulation of relative velocity on our simulations page that you might be interested in having a look at. In two dimensions, the relative velocity equations look identical to the way they look in one dimension. The main difference is that it's harder to add and subtract the vectors, because you have to use components. The train doesn't have a y-component, because it is traveling west.