well, people in Russia do take long train rides like even from Moscow to Vladivostok - 7 days - instead of air. And 2-3 days train rides are nothing exceptional. When you have more time than money...
We generally don't, most of the passengers on these trains only go part of the route. Train trips taking 2-3 days (like Moscow to Urals) used to be more common, but flying has become cheaper years ago.