I’d probably be willing to pay a premium for a place that backed up to a Class 1 mainline. 
I spent years living under a runway approach to a major metropolitan airport/hub. Aircraft flew low over the house on a regular schedule, many times/day. The noise and vibration were no better than living in close proximity to a major rail line and may have been worse.
After a while the only time we noticed them when when we were on the phone and had to stop speaking for a minute or so or miss a line from a TV show (probably better off for it!).
The advice to see for yourself is good, but just a brief visit won't help. You need lengthy exposure to see if you will get used to it. Some people do--I'd love to live closer to the tracks about a mile from me--but some cannot. Perhaps visit a friend or relative that lives near one or find a campground that is close to one and spend a weekend there.
Some of my unit's events are very near tracks, and I usually find that I can hear some of the passing trains--with horns--on the first night but not the second.
This response addresses only the initial question and not the further questions of resale value or potential eminent domain.
@Number 90 posted:Deciding to buy within easy earshot of a railroad is a very personal decision. If you like to hear trains and are willing to risk lower resale price, an unhappy wife, agitated and unreasonable neighbors, as well as having to cross a mainline track when coming and going from home, then this might work for you. If having any of those trade-offs makes you even slightly hesitant, then perhaps a different location would be better suited for you.
I hope that you are able to look back a few years from now with confidence that you made the right decision.
I spent 4 years in Terre Haute. All of the above is true. CSX and Norfolk Southern - all hours of the day. Getting "railroaded" is a local colloquialism. The sound of trains in that town is constant.
Watch the hotel scenes in 'My Cousin Vinny"!!! LOL
I grew up 100 yards from the CSX S line in N. Central Florida. Aside from having to wait to talk on the phone until the train passes. You might have to crank the volume up on the tv or radio from time to time throughout the day. But it really just turns into background noise. It becomes natural to hear as an airplane flying over, or the dogs barking. You really get used to it. I still love listening to the engines hum you a lullaby as they come and go through the still of the night. In adulthood I managed to purchase a house a couple blocks away from the same tracks, just on the other side of town.
Or Elwood’s digs in the Blues Brothers. I think he says the el goes by so often you get used to it.
