At one time, there were news agents who walked through the coaches selling such items as pop, sandwiches, chocolate bars, and newspapers. Later, waiters walked through cars selling food items. There were certain items which were not allowed to be sold after crossing certain provincial borders or crossing the US border either way.
Later, there was a dinette car for the convenience of those who did not go to the diner for meals. It had a counter which ran the full length of the car and two or three staff for providing service. Since the kitchen was at one end of the car, it resulted in a long walk in serving at the far end. Like other on-board jobs, it was hard work for the staff.
Those who slept in the day coach at night could rent a pillow from a trainman who would walk through the coach in the early evening. He would pick it up in the morning.