Nothing is more enjoyable on a train than reading a book. You have a lot of spare time and no mundane work to bother you. Whenever I have to go on a long train journey, I look for books lying unread in my shelf for months together. The moment the train starts moving, I open the book and lose myself fully into it, lifting my eyes only occasionally to see the visuals outside. Appropriate breaks are thrown in to chat with a fellow passenger or for food/tea. By the time the journey is over, I am wiser - hopefully.
I particularly like the night in the train. The illuminated compartment contrasts with the darkness outside - some flickering light sometimes appearing in the distance. Lying on the berth and waiting to fall asleep while the train is moving is quite an experience.
I don’t know why some people prefer to reach their destinations without having to spend the night in the train. To me, a journey without a night in the train is incomplete. The experience of so many people sleeping together in the compartment, the sound of the moving train and the darkness outside is irresistible. It is a welcome break from sleeping on a bed surrounded by concrete and mortar. Occasionally, I love to be mobile while I am fast asleep.