The funny thing about GM, though a car company, is they developed that ubiquitous Diesel engine exterior design in the 1930s, already. They built the big "Electro-Motive Division" plant in LaGrange, Illinois to build them. And their man in Dayton, Charles Kettering, had a hand in designing the engine itself.
Im not sure about that tri-level dome car design...whether it went into production? The publicity is interesting, the way they treat fluorescent lighting as a new concept. I think it was introduced in the 1930s, too?