One idea it’s exploring: the construction of a sprawling network of underground subway tunnels to shuttle the missiles around like a mobile doomsday train. As one does.

As first reported by Inside Defense, the Air Force Nuclear Weapons Center will award several study contracts next month worth up to $3 million each to research the idea. A broad agency announcement from the Air Force describes the hair-raising concept, intended to keep the weapons secure through 2075, as a system of tunnels where nuclear missiles are shuttled around on rails or some undefined “trackless” system.

The advantage of the world’s deadliest subway: During an atomic holocaust, mobile missiles are harder for an adversary to target than a static silo. Missiles could be positioned at launch holes placed at “regular intervals” along the length of the tunnels.