Tensions between the U.S. and Russia are dangerously high. Both sides are complaining that the other has ignored military norms in international airspace and at sea, both have accused the other of violating treaties designed to prevent large-scale war, and both are developing systems to counter the other's strength.
But, while Russia works on new tanks and bombers and the U.S. tries to get its second fifth-generation fighter fully operational, each side is also looking to a nearly forgotten technology from the Cold War, nuclear-armed trains.
The idea is to construct a train that looks normal to satellite feeds, aerial surveillance and, if possible, observers on the ground, but carries one or more intercontinental ballistic missiles armed with nuclear warheads.
These trains would remain in a fortified depot during normal operations. During periods of nuclear brinksmanship, though, they would be dispersed across the country to provide a credible counterstrike if the enemy fires their nukes first.
The trains, if properly camouflaged, would be nearly impossible to target and could launch their payloads within minutes.
Russia got the missile cars to work first and fielded an operational version in 1991. In the early 1990s, America built prototype rail cars for the Peacekeeper Rail Garrison missile system and tested them, but then the Soviet Union collapsed and the project was cancelled.
Now, Russia has leaked that it is designing and fielding a new version of the trains. The Barguzin missile trains, named for a fierce wind that comes off of Russia's Lake Baikal, will carry six RS-24 Yars missiles each. Yars missiles can carry up to six independently-targetable warheads with 100-300 kilotons of explosive power each.
The missile cars and fuel tanks are to be disguised as refrigeration cars and will be indistinguishable from regular trains if the weapons live up to the hype. Each will be able to deploy with its own security force and missile personnel for up to 28 days without resupply.
America has been flirting with restarting its nuclear trains, but it doesn't seem likely. The Air Force awarded study contracts in 2013 to look at the feasibility of a "nuclear subway" system where missile launching trains would have dedicated tracks underground.
But, budget problems that were biting at the Pentagon then have continued to hound it, and mobile launchers are expensive. Plus, most Americans don't like the idea of nuclear trains running under their feet any more than they like the idea of nuclear trucks driving through their local streets.
The feasibility of Russia's plans is also suspect. After all, the Russian Defense Ministry is running into worse budget problems than the Pentagon. It's ability to fund a nuclear-armed train while oil prices are low and its economy is in shambles is questionable at best.
Right now, America's main counter to Russian nuclear trains, and any other intercontinental ballistic missile launchers, appears to be its missile shields in Europe which could intercept many outbound nuclear missiles.
China has also flirted with nuclear trains. In 2013, Chinese media – whether accidentally or on purpose – leaked footage of a train modified to hold DF-31 and DF-31A missiles which can carry a single 1-megaton nuclear warhead. There were some questions at the times about whether or not the system was truly operational.