Or for the interested, TileMill would be better as you can print exports in PDF as vectors. I spent a great deal of time trying to manually create transit maps for one of our 'archaic' transit agencies, and this was before Mapbox Studio's time. I use Studio a bit, but TileMill does the better job as it caters better for offline usage.

I do agree with others though that it would have been a great amount of effort to invest in understanding CartoCSS for his requirements, and getting to create it.