Security on a plane ensures that once the plane is airborne, there is little that someone can do to interfere with the flight.
But a saboteur can attack the rails at any stage of the journey or even launch a missile at the train.
Whereas no one has ever fired a ground-to-air missile at a commercial airliner, right?
Here's another argument in favor of trains:
How many hostage crises, hijackings, or massive acts of sabotage have been carried out against trains in the U.S. (or using trains as weapons against, e.g., buildings) over the last fifty years?
Now, how many have been conducted against airliners?
So, what evidence do you have that that is going to change?
Regards,