There's a lot of potential for animation of Google Transit data, and we're just starting to see it explored. Some results will be rich with information, differentiating various kinds of service so that you can see how they dance together. Chris McDowall's animation of a day's transit in Auckland is less informative but correspondingly more meditative. Buses, trains and ferries are all rendered as earnest little tadpoles (or comets, or sperm, or viruses, depending on your sense of scale).
It nicely illustrates the point that frequency is what makes a route into a line. The line that goes really solid during the peak is the Northern Busway, which is far more frequent than any of Auckland's rail lines.