Getting the window frames to smooth properly has become somewhat of a challenge. The poly-count is high enough already for this model, so I'll just paint the windows and doors on.
Here I've broken the model into two parts to better manage it and to add some color (this is one of three color schemes I'll be making for it). I also need to model the head and tail lights. And then there's a piece that goes in the front for the monorail and also the air intake grills I still need to add.