[alexander_busek]

What makes passengeers think that they are going to get through security to get on a train any quicker than it will take them to get on a plane?

Well, for one thing, it could be quicker because - after a superficial security check before boarding - security personnel could move through the cars after disembarcation, conducting a more-thorough search.

You can't do that on an airplane.

Further, a much more powerful explosive charge would be necessary to cripple a train - and even then, there would be survivors (as opposed to mid-air detonations).

Further, it would be much more difficult to hijack a train and/or divert its course.

Finally, in the event of, e.g., a hostage situation, it would be easier to get law enforcement officials onto the train.

So, all in all, less security would be needed, and the consequences of a breach of security would be less severe.

Regards,

[a fool in paradise]

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.

[dirtboy]

Further, a much more powerful explosive charge would be necessary to cripple a train - and even then, there would be survivors (as opposed to mid-air detonations).

Google 'Madrid 3/11' and get back to me about how al Qaeda can effectively wreak complete political havoc by targeting trains.

[MrEdd]

You left out the biggest reason.

With thousand of miles of track there is zero reason to plant explosives on the train instead.

Just stop a truck bomb on the rails