I love the trains in Thailand and they give you a retro experience and are more interactive than a plane as you can walk around and do things like take a shower or go to the dining car. I know of only one plane where it is possible to shower and that is going to cost you a few bucks for the privilege on the Airbus A380 in first class.
You can take trains north almost as far as Myanmar or you can go to Malaysia if you head south, or you can get off and head to the resorts near Phuket or the Gulf of Thailand beach resorts on the Gulf of Thailand coast .
When you buy your tickets you want to have a lower bunk and you want a car that is further back on the train, the further the better as you will be hearing the horn all night if you are at the front of the train. If you can afford first class and there are two traveling then it is worth paying a little more as you sleep better knowing the door is locked and you trust everyone in the compartment. In 2nd class I always sleep with half an eye open, although I’ve never had any problems.
When sleeping on a boat, I have found that it is more comfortable to sleep in the direction of travel from beam to stern than in the direction of travel. It works the same way on a train, as the rocking from side to side is reduced when you sleep facing the direction of the train. There’s more force to stop and start than side to side, so the first class isn’t any better in that regard as far as sleeping is concerned. If there’s a lot of rocking, you’ll be tense all night trying to keep your balance.
Things to bring to help stretch the budget would be your own coffee or tea, whichever you prefer. I buy Nescafé in individual packets, they last forever and take up no space and couldn’t be easier to prepare. They are also a great deal with a touch of over 3 baht per cup which is $0.20.
Since they have hot water available on most trains in Asia, I also buy a cup of soup, I always get it in a plastic container instead of paper so I can reuse it for the couple packs of ramen noodles I also buy. It costs 14 baht for the cup of soup and 6 baht for the ramen, around $0.20.
I always stop for a bite to eat before I get to the train station to save money there too. I am a supporter of orange slices, maybe for you they are gummy bears. You’ll want something to snack on on the long drive. They usually have a food attendant who comes as soon as you leave Bangkok and gives you set dinner and breakfast, 150 for dinner and 90 for breakfast. I always try to overlook that, though I ask others who find it to be good food. However, I go to the dining car and grab a plate of whatever and power up my computer. The dining car is usually very entertaining at night as all the locals sit around and drink cheap beer and cheaper whiskey which you will also be asked to join which I am sure will result in some laughs on your way into the train in Thailand. .
