Are all the long distance trains back to normal yet? I assume it will be one person to a seat, so that will mean higher fares, right?

SRT are only allowing their 3rd and 2nd class long distance trains of 50% capacity and will not accept passengers who'll just turn up and don't mind standing. The fares are the same, you'll have to book the train about 4 days or more in advance as they sell out fast.  Sleeper carriages are not affected as social distancing already exists.  About 80% of the services are up and running. You'll have to check first at your local staffed station as their information is more accurate than their website.