Train trips in Vietnam are the preferred travel mode for many people as they like the sights and the sounds that you don't get when you take a plane. You also get snapshot moments where you can see into the communities as you pass them by. The Vietnamese countryside is visually stunning with amazing gradients of green from the moist moss black greens of the jungles to the hypnotic electric green of the rice paddies and offers lots of different sights like the kids going to school, dogs play fighting, women hanging the laundry and people taking naps in hammocks. Vietnam is one of the best places for train trips if you like this kind of voyeurism.
Trains in Vietnam are very cheap; you can travel from one end of the country to the other and not spend $50. You can get for instance an overnight train from Saigon to Nha Trang for about $15USD; this would be a soft sleeper with 4 people in the cabin. You can get really cheap and get a hard sleeper for the same trip for about $12 where you share the cabin between 6 people, and if you are real hard core you can go with a soft seat for around $10, which I would not recommend as these compartments are over crowed with luggage. The cheapest travel would be by hard seat..
Trains also are attractive in Vietnam if you have a lot of luggage as they do not weigh it. You can bring as heavy as you carry and load by yourself and not have to pay over weight limits which is great for scuba divers and surfers. Lets say that you come to Vietnam on a cheap flight from Hawaii, most US international flights allow you unto 70 pounds or 31 kilos; in Asia many flights are 22 kilos max including you hand luggage which they will weigh if you are close to the limit. If you take an overnight sleeper you can also save one night of hotel accommodations which is a great budget stretcher to keep you on the road longer.
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