In Sri Lanka Railway lines were built by the British. Most part of the railway lines are only one track. SoTravel to long distance need more time.
But basically Beautiful views.
Mountain area is very beautiful.
To see the beauty of the nature, You better travel by the train between Peradeniya and Ella. And also from Habarana yto Trincomali.
To see the beauty of the ocean, then better travel between Moratuwa to Matara.