Upvote:3
From my own experience, I would say that trains are pretty safe in Asia, probably more safe than buses or taxis. I took the train from France to Beijing, and rode on many trains in China, Vietnam, Thailand and Burma. I don't think there are trains in Laos.
I never heard of any major incidents. It's possible that people steal your stuff, especially at night when you are asleep, but that can happen in France as well.
I remember in Vietnam, people would sometimes throw rocks at trains, and so the windows had wire-mesh for protection. I'm not sure how common this is nowadays.