If they are cooking it in a convection oven, that is IMHO the best way to cook a pizza hands down! The air circulation removes the excess moisture from the toppings that usually make the crust soggy. You get a nice crisp crust on the bottom, it's very hard to burn the crust, and the cheese gets perfectly browned. From a microwave in the cafe car, not as much.
I agree. Pizza is popular, and cheap - along with easily & quickly heated in a convection oven. I don't know why Amtrak doesn't serve more pizzas in the dining cars. I think I remember reading that the pizza on the children's menu in the diner is just the DiGiorno, but I wonder if they cook it in the convection ovens?
And as far as "meals in a row", I think I've done 6-7, but may go for a personal record this summer of 12*.
*I often skip some meals during "mealtimes" on layovers in favor of just grabbing a snack from the cafe car when I **retrain.
**Can you say "retrain"? If you "entrain" when you board and "detrain" when you leave, can you "retrain" when you're getting onboard again?