What is a Pullman porter in bud not buddy?

A Pullman was a type of railroad car that the seats could be converted to bunk beds for sleeping (on long trips) The porter was the person that looked after the occupants of that car, Their duties included: The porter or attendant is required to wait upon passengers, assist them with their baggage, shine shoes, prepare berths, keep the car, linens, and equipment in orderly and cleanly condition, attend to all other duties requiring his attention and carry out such instructions as the conductor, car owner, or operators may give him.