[Justa]

That makes no sense. Air breaks are FULL ON when there is NO air pressure in the lines.

The brakes were either not set initially or were released prior to the train rolling.

It was not a systemic failure it was either operator error or sabotage. Probably the latter judging by the fire.

Someone released the brakes.

[thackney]

Air breaks are FULL ON when there is NO air pressure in the lines.

This is a train, not a truck. The systems are not the same, and for good reason.

It was not a systemic failure it was either operator error or sabotage.

You left out incompetence.