In my case: my frequent travel by train is around 3 to 3.5 hours one-way, on routes that would be around 1h40m to 2 hours by car. Using a $0.30/mile figure for driving, the train is around the same price, or a bit cheaper, than driving myself, so long as I am using multi-ride tickets.
However, the train is a comfortable environment for me to do other things. I can read, write, and do quite a bit of research work; I can comfortably use my laptop and usually have a decent internet connection.
If I drive myself, I can do very little else but drive during the time; if I have someone else drive, I can do some things, but it can be quite difficult and rather nauseating, no matter how nice the car.
Thus, my choice is usually between a 3.5 hour trip where I can pretty much do much of what I'd be doing were I not traveling during that time, or a 2 hour trip that will actually hinder the better uses of my attention: the shorter duration trip ends up taking much more of my time.