I have lost all sense of days of the week, here in Vietnam. It was a Monday, late in the day, when we left Hanoi.
The disadvantage of the sleeper, (there are three Express per day to Ho Chi Minh city), is that you have to check out of your hotel by about 3 pm but do not need to get to the railway station until 10 pm

The traditional beds, which I have seen at the Vietnamese house in Hanoi, and again in the Fine Arts Museum in Hue, is a large wooden, very wide, divan. There are no mats on it. I was told that only the old people were expected to lay on mats, otherwise it is solid wood, the floor, or possibly a hammock.

Maybe the bed experience gives you a foretaste of sleeping on the Express train. Though it was not the bunk bed that kept me awake, it was the noise of the train on the tracks. By golly, that track is rough!!! Every so often the tone changed, perhaps when going over a river crossing. It can only be described as a din.

The other occupants of the four bunk compartment was two Vietnamese ladies, possibly daughter and mother. Both very shy, and not speaking English. The older lady had a lovely smile - she was tiny, with rather fetching black velvet wound round her hair, a pink cardigan, red blouse, and black silky trousers. Her teeth were blackened - the second old lady I noticed with this effect. Perhaps it is from eating betel?
There was a large vacuum flask on the floor. I noticed the Vietnamese going to fill up the flask from a hot water point at the end of the corridor.
In the morning, a man came round and handed out pot noodles, so you could have the traditional noodle breakfast. I added hot water to mine and it was actually just right to eat at that time of day.

To return to the bed subject, regading in the hotel in Hanoi ,there is a resident old lady there who sleeps on a wooden bench, just inside the entrance. I am amazed that anybody can do this - it seems an absolutely unforgiving surface.

The train left on time, 11 pm, and arrived in Hue at 10.15 am where the heat is obviously much greater than in Hanoi, but there was marginally less traffic - the main problem, for any visitor, is the cyclo drivers, who follow you around absolutely determined that you should hire them to go to your destination, even if it is only a few yards.

Necessary to learn a few words of Vietnames - very quickly! Like No Thank You.