Bombardier are clearly so proud of their new "fast, efficient & eco friendly trains" that they're running advertisements for them on the system.
Perhaps a condition of getting the contract from TfL to supply the S Stock trains was to run ads putting across Bombardier's by-line of "the evolution of mobility".
Although it's not as if we have a choice of which trains we take when we're on the London Underground. But, maybe I'm wrong. Perhaps there are some people who wait around at platforms until a shiny new train comes along. If you've a bit of time to spare maybe it is worth getting on a nice air conditioned eco friendly train!