What was surprising is that they have very modern high-speed trains, and super new train stations (most of them built just a few years ago). The country is huge but very well connected by train (and air; we first flew to the far west, and then came back east by train and visited a few cities along the road).
For one of the trains we bought regular tickets, but the ticket inspector friendly insisted on us to get an upgrade to the "lux" class :) (probably the regular class was busy), which was a good decision; the upgrade was absurdly cheap, and worth it (4-people compartments, very spacious and comfortable) due to the length of travel (several hours).
Another fun story: in another train we've been in an "open space" w/o compartments; it had TVs on the room which first played Michael Jackson concert, and the some TV series :)