Again your message proves that you think about the people outside the vehicle as A-class citizens and those aboard as B-class citizens.
There are 300+ people on a train and 4000+ on a cruise ship, those things don't need to be used as a weapon to cause a very sad day for the whole Nation in terms of human lives lost.
It is extraordinarily difficult to kill or maim people on land using a ship as a weapon - it will simply run aground, and there are guides aboard on ships big enough to cause damage when they are near the shore, as an additional defensive measure against incompetence and hijackings (insert obligatory Ever Given meme here).
For trains, the situation is similar. Even if you manage to bomb a train, it's unlikely to cause a major, deadly disaster. Rail infrastructure is built with the assumption that trains will get out of control, and the industry has nearly 200 years of experience.
Trains, ships and airplanes are ineffective weapons that need a lot of knowledge to turn into an actual weapon. A truck is way more effective: easy to acquire, easy to use, and even right in the middle of an attack people will assume that the driver has lost control or has medical issues instead of being a terrorist.
I would rather compare the train/cruise ship to a packed theater/stadium, rather than a commandeered aircraft used as a kinetic weapon. You have potentially thousands of vulnerable people in an enclosed space with no realistic means of escape. The idea that a bombed train isn't going to be a major disaster is baffling to me. Train derailments invariably cause massive casualties to those on board. Heck, lock the doors and start a fire.
There are 300+ people on a train and 4000+ on a cruise ship, those things don't need to be used as a weapon to cause a very sad day for the whole Nation in terms of human lives lost.
Even if the thing is not used as a weapon.