Hi Chantelle, You have over 10 trains to pick from. I think this site will answer all your Thailand rail questions: http://www.seat61.com/Thailand.htm Good Journeys!

LAST TIME i TOOK IT 1985 WAS JUST OVERNIGHT,

seat61.com is a great site they even instructions to check the schedules in on Thai site. We were there and got the overnight train a few times from Surat Thani to and from Bangkok. If you get a sleeper it's fairly comfortable and lasts about 12-13hrs avg. It should be booked in advance as sleepers can fill fast. If your trying to get to the islands Koh Phangan/Koh Tao/Koh Samui, I would suggest the Lomprayah high speed Ferry out of Chumporn FYI http://www.lomprayah.com/E/route.htm If you take the train to Surat Thani you then have to Bus to Don Sak then Ferry to the islands. Have a great trip!