Just a couple of comments on the overnight train between Bangkok and Udon.
My first choice is first class. If you don't book two seats, you may end up sharing the compartment with someone else of the same gender. Tha could be good
![Confused :?](./images/smilies/icon_confused.gif)
. One of the things I really like about first class is that you can take a quick (though cold) shower. Makes me feel a little fresher when I arrive
![Razz :P](./images/smilies/icon_razz.gif)
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Second choice is second class sleeper, lower birth. The upper birth sways way too much, and many of them get a freezing cold blast from the air conditioner. Get the lower if at all possible
During times of heavy travel, particularly around Songkran, the trains and many busses
will be packed to the rafters. Some airplanes would too, if the airlines were permitted to do so. Songkran is the time families get together, and if necessary, people will travel like sardines in a tin from their places of work to their villages, then back again. Its too bad you didn't take a picture of people climbing out of the windows. I would have liked to have seen that
![Razz :P](./images/smilies/icon_razz.gif)