It is so fun to talk about travel, think about travel, plan travel . . . I like to see everyone jump in with their favorite tips and tricks.
You guys didn't like my travel "rules" lol, I was thinking those are maybe for a different kind of travel, backpacking and hostelling in Europe, etc. Also you took them kind of literally. I always interpreted "never bring anything you would hate to lose" as meaning don't bring things of important sentimental value like family heirlooms, etc, irreplaceable things. And maybe that applies more to traveling in places you're unfamiliar with, or riskier places than an American Amtrak train. But, the rule just acknowledges that when traveling, you want to expect the unexpected, and that you might find yourself in situations that you don't have much control over. Also that when you are a tourist in a foreign country, you are a target for theives and con men, that's just a fact, people may try to take advantage of the fact that you are on unfamiliar territory, can't read the social signals, maybe can't speak the language and don't know where you're going, etc.
So yeah, I've relaxed that one quite a bit on my Amtrak jaunts to Canada
The other rule about bringing twice as much money and half as many clothes, true, maybe you don't actually carry it on you in cash or traveller's checks like we used to, but it's best if you have
access to more than you think you need, especially if you're going to Europe! yikes. If you're travelling overseas or in a third world country, it's best to be prepared for delays, when I went to Peru, there was a chance of getting stuck there by transportation strikes, also by weather which prevents flights in and out of the mountains, a person might have to pay for several days of hotel stays on top of what they planned for.
I realize credit cards have changed a lot of these concerns, but budgeting for a trip is something you get better at with experience. The OP sounded like he hadn't travelled a lot, so I threw my old "rules" out there and I"m glad they became part of the discussion topic.
It's different packing for a long trip when you have to haul your stuff around without a car, the "half as many clothes" is a very good idea for most people who aren't experienced travellers. Besides, a lot of times it's fun to shop and buy a few new things as you go, it's good to have some room in the luggage for that.
This is all kind of off topic for "where to put your luggage on an Amtrak train"!
but it's fun to talk about the old adventurous travel of years ago!