Amtrak is the only operator running cross-country passenger trains in the United States, which goes some way to explaining why a one-way private-room fare on a flagship route can run into the thousands of dollars. With that kind of money on the table, the real decision is usually between two cabin types: the roomette and the bedroom.

Both come with the same core package — access to station lounges, a first-class attendant, and all meals included — so the choice comes down to space and, crucially, plumbing.

A roomette measures about 3.5 by 6.5 feet (roughly 20 square feet) and sleeps two. By day it's two facing seats with a fold-down table, reading lights and power outlets; at night the seats convert into an upper and lower bunk. It's compact — solo travellers have reported feeling squeezed — but the jump up from a coach seat to a lockable room of your own is still significant. The catch: showers are communal, and there's no in-room toilet either, except on Viewliner cars, which have a toilet but still no shower. If the idea of flip-flops in a shared stall someone has just used bothers you, think hard before committing to a 51-hour run on the California Zephyr, the longest route in the network.

The bedroom doubles the floor area at roughly 6.5 by 7.5 feet and takes three guests: a full-width lower bed, a smaller upper bed, and a sofa with a parallel seat once everything folds away in daylight. The window is larger than the roomette's, so the views are better too — a real plus on scenic rides like the 35-hour Coast Starlight. The headline perk, though, is a private sink, toilet and shower en suite. Modest and a little awkward to manoeuvre at first, but for anyone who values privacy and a proper freshen-up mid-journey, it can justify the extra cost.

There are a few other configurations worth knowing about. Accessible bedrooms mirror the standard bedroom layout with space for mobility aids. Bedroom suites combine two adjoining bedroom units. Family rooms fit four but, like roomettes, have no private restroom or shower.

The shorthand for travellers: roomette if you're on a budget, travelling solo or as a couple who don't mind close quarters, and happy to share a shower; bedroom if you're three people, value an en-suite bathroom, or are simply settling in for two nights or more on the rails. Booking either tier for less than an overnight is probably overkill — but on America's marathon routes, that bathroom question decides a lot of trips.

Story via Explore.com