I used my scanner daily during my commute on the train. Conductor even gave me the freqs and an old timetable. My suggestion is just be discreet about it (use headphones). I don't think there is any rule forbidding it.
I have used mine and my amateur HT on several trains. Use a headset to avoid bothering others and you shouldn't have any problems. With the possibility of railroads moving to some form of digital (NXDN?), there won't be much to hear. I have also used mine on the Megabus without any problem. Just remember to check the state you are traveling in if you do not have an amateur license.
I used my amateur HT as a scanner on a two-day trip on Amtrak's Coast Starlight from Los Angeles to Seattle. I didn't have a headset for it at the time, but most of the time I was in my compartment where others couldn't hear it. When I went into the public areas of the train, I kept the volume turned down to the point where I could barely hear to keep from bothering others. I never had any issues with ans of the several conductors on the train.
I'll be taking the Amtrak Sunset Limited from New Orleans to Los Angeles in September and I have purchased a headset for my HT just in case...
I used my scanner last year when i was on the Empire Builder and the Cardinal going to Cincinnati to meet my brother and do the Dayton Hamvention, never had any sqwaks from anyone on the trains at all, i did use my Ipod headset, so that was good. As has already been said, use headphones and ya should be good to go. Another bit to be aware of, when i was on the Cardinal from Chicago to Cincinnati they were in quiet hours, so be sure to use a headset and keep the volume low. Have a groovy trip on Amtrak, you`ll defenitely enjoy the ride . N9NRA
I've been riding Amtrak trains from California to Quebec and Washington State to Florida since the mid-1970s with scanners/monitors without once having a problem with crews or other passengers, but as has already been mentioned, always use earbuds or earphones and keep them turned down, especially if you're sitting right next to another passenger.
The Amtrak website itself says the same thing,
"To maintain a pleasant environment for all passengers, we require that when using radios, CD players, DVD players, TVs, and all other audio/visual devices, passengers use earphones or headphones, and that the volume be kept low.
Many of my trips have included the Empire Builder between CHI-SEA (Trains 7/8) and CHI-PDX (Trains 27/28). A few times crewmembers have seen my scanner and given me tips such as "If you're listening to us, we change to Channel 76 from Spokane to Whitefish," but my experience has been that crews in the west tend to be more laid back about it than in the east.
In general, don't expect to hear a lot of radio traffic for your particular train most of the time, other than a quick "that'll do, Amtrak 27" and "Amtrak 28, highball Pasco" as the conductor radios the engineer that the train is ready to stop at/leave each station.
Bottom line don't cause any attention to yourself and you won't have any problems. I have had sc anners on a lot of Amtrak trains and never had trouble. Also use earphones to not to distrub other people
I was on the Empire builder back in November and had my scanner on with no headphones but Had the volume low. My room was directly across from the sleeping car attendance room and he had no issues with it. In fact we were actually talking about the radio at one point. I would say just be respectful of everybody around you and you should ok.
Disclaimer The sleeping car tenant as well as the rest of the crew know I was a conductor for another railway.