Since I started this thread, I'm coming back in to clarify what I was asking. I'm not looking for a special gluten free or wheat free meal. All I want is to find out if the eggs are a mix with wheat, if the hamburger is mixed with bread crumbs, and if the steak is marinated in something with wheat like soy sauce. If we can safely eat these three things, we're all set for all three meals. Almost all chain restaurants willingly give customers this kind of information. All I can get out of Amtrak is their pat statement that they don't have a gluten free menu. Thousands of people are giving up wheat because they can't digest the new wheat that has been altered by hybridizing until it's causing all sorts of ailments. Amtrak will eventually have to respond to this. For now, if they could just let people know if wheat is in everything they serve.
A lot of food doesn't really need refrigeration despite the label, or only needs refrigeration after it is opened. For example, you could have great sandwiches of a nice cheese and sliced almonds or apples on rice cakes. Peanut butter, avocado, salsa or dried berries would fit in there, too. I believe Trader Joe's jerky is gluten free, worth checking. You could make up baggies of your own trail mix. For breakfast, pack some instant cereal (such as cream of rice) and get hot water. Dress it up with mandarin orange slices or dried berries. So there are lots of choices of tasty things you can pack without refrigeration or cooking needed. (Pack a small cutting board and a good knife, perhaps a couple of mugs and spoons if you are going to make your own cereal.)
Don't know about Amtrak eggs, but the continental breakfast includes grapefruit and yogurt (I think Yoplait), and has oatmeal as a choice. Although technically oatmeal is gluten free, it can be contaminated with other gluten grains so whether you'd want to eat it depends on how sensitive you are. I'm sure Amtrak doesn't pay extra for certified gluten-free oatmeal.
Salad dressings are served on the side, you might want to take your own bottle just to be sure. Perhaps someone will post the brand and you can take an "acceptable" list.
Also don't know about the hamburgers and steak, the steak definitely has something added to it. You might do better with chicken or salmon, especially the meat often available to be added to a salad. As others have said, ask on board. A baked potato is also often an option and you can get it plain then add your own choice of toppings. Potato chips are served at lunch but have the same issues as oatmeal, at least you can take a list of acceptable brands and compare it to the packages on board, same with ice cream.
Are you in sleeper or coach? I ask because your meals are included in the sleeper price, so wasting much of any meal might not be so painful, and that is probably what you'll be doing every meal. The dining car doesn't have a la carte service, and the cafe has a lot fewer choices.
Have a good trip!