As far as bringing your own food, you would bring a few things anyway I'm sure, so maybe a helpful topic to continue this discussion is what kind of healthy portable food is good to bring for snacks on the train.
I went 36 hours on the train and only purchased coffee and bottled water on board, I brought rice crackers, cut up cheese, carrot sticks (could have been other cut up vegetables too), apples, corn chips and the main thing I had was fresh juice from my juicer that I froze in plastic water bottles, I packed this in a small soft sided cooler, put that in a tote back with the rest of the stuff, the frozen juice kept the other stuff cold til the very end. You could go longer with ice in ziploc bags since ice cubes are available on board. Oh I had trail mix, homemade from raw nuts and dried fruit.
I bring my lunch to work every day, I have almonds, dried cranberries, candied ginger, chocolate stashed away there and carry apples when they are in season, sliced cheese, carrot sticks and hummous or homemade cream cheese spread.
Oranges keep well too and are refreshing, all you need for all this stuff is a jackknife, some paper napkins, etc.
That fizzy drink product called Emergen-C is a great thing to travel with, I always bring some, and a plastic cup but they have a pitcher of ice water and plastic cups in the bistro car here too, so you could bring all sorts of drink powders if you like that sort of thing. The Emergen-C is good cause it has vitamins and minerals that help your immune system and help with stress.
You could put peanut butter in a little plastic tub with a lid and bring a plastic knife and have that on rice cakes. Also I have a good coconut macaroon recipe that is wheat free and those travel very well and are filling and nutritious.
