1. He is on the train. He is sitting in the seat. He takes a nap.

2. He is on the train. He is sitting in the seat. He goes to sleep.
3. He is on the train. He is sitting in the seat. He goes to bed.
4. He is on the train. He is sitting in the seat. He begins/starts to sleep.
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Can we use all the expressions? Are they the same? Actually there is no bed on the train. He feels sleepy and sleeps in the seat.

3 answers

1 and 2 are fine, but I wouldn’t use 3 or 4.
Thank you.
What does 'go to sleep' mean?
Does it mean that he goes to a place to sleep? Or does he fall asleep in the same place?

1. He goes to a place to sleep.
2. He fell asleep.
It can mean either one.

He went to his bedroom when he was ready to go to sleep. (intentional)
He falls asleep during class sometimes. (unintentional)