these things too shall pass away

immovableobject There are walls in Atlanta that are designed to stop a freight train.
A concrete sandwich, with two ferro concrete sides filled with gravel, with a garnish of steel bands. They are in place in front of the supports to elevated sections of the MARTA train lines. They protect these supports from a runaway freight train...or a passenger train, which is usually travelling faster and would have a greater impact. Of course, any passengers would be converted into mush, but the rapid transit lines need to be protected.
The amount of force generated by a freight train... hundreds of tons of product, hurtling down the silver rails at great speed...is immense. The promise of an immovable object that can control this unstoppable force …this is what we have here.
To date, these walls have not been tested.