Of course they’re different but the principle is the same. Air pressure is required to keep the brakes from applying. If the brake cylinders are not pressurized the brakes are full-on.
It was not a failure in the brake system. When pneumatic brakes fail the vehicle won’t budge. It was operator error, aka ‘incompetance’ in your post, or sabotage.
For as long as pressure remains in each air reserve tank on each car. That gives the train operator time to set the hand brakes. Unless he left the train with no one in attendance, like they did here.
The brakes held for at least an hour. Then the bled down enough to no longer have sufficient pressure to hold the train on the incline.
When pneumatic brakes fail the vehicle won’t budge.
Again, this is a train, not a truck. There are no springs to hold the brakes closed. On a highway with a failure in the brake system, broken air lines, etc, you can drag the rig to the side of the road, let other traffic through and call a tow truck. Trains don't have that luxury, so they don't use spring brakes held open by air pressure.