Back in the 70s DH and I used to go on business trips which meant an early start. We would leave our carriage and go off to the dining car, which was First Class, and sit in luxury eating a lovely breakfast with as much toast, tea and coffee as we could stuff down. By the time we'd finished the train would be rolling into Birmingham or wherever and off we'd go.
Obviously on a long trip you need to eat, but I do try to plan sensibly with non smelly food that can be eaten without too much mess. It's the non stop eating that annoys me. On a train or bus, in the cinema, in the street, even eating food in a shop before it's even reached the checkout. People seem to be unable to cope without food in their hands at all times.