If you want to travel to different cities in Vietnam, there is not an easier way than catching a train. You even don’t need to book a ticket in advance, just go to the railway station, purchase a ticket at the ticket office, then proceed to the waiting room and get to the train when it’s ready.
Depending on your trip, the available trains will vary. I booked the SE6 and SE7 trains; both have 4-berth cabins with soft sleepers that I can lie down comfortably during long trips. However, hygiene has been always an issue of the trains. The SE6 train was acceptable but the SE7 train was very dirty and I even couldn’t breathe when using its restroom. It was just a horrible experience.
I found out that there are some cleaner trains but they are express trains for some specific routes only. Now, take a look at the trains I took in 2017.