What is it with trains that is so exciting? Is it the sense of adventure? Or of passively travelling (as a passenger) but in such a way as to see and recognise landmarks? On a plane travel is too quick and nothing identifiable is ever really seen except for huge landmarks.
With trains you travel at a speed where all things are viible but at a different speed and from a new perspective. Slightly aloft and different from the road but somehow remaining similar but yet different.
As the train passes through known and unknown places a glimpse can be had, but it is fleeting and all too quickly its gone again. There is no way to resist the sheer power and speed of locomotion.
Even if you wanted to linger, you can't and all too quickly you are moved on in your passive observation to whatever lies ahead.
Perhaps part of the mystery of the experience of travelling on trains is that a train can only go along a particular route. A route actively chosen by someone else to move people efficiently to some place else.