By the late 1970s satellite surveillance had improved targeting and strategic missiles had become more accurate. This made missile silos vulnerable and mobile launchers [sea, road and rail] more attractive. Both the USA and the USSR began developing rail based launch systems.
USSR RT-23 system
In 1987 the USSR deployed rail mounted launchers for the RT-23 missile [NATO name SS-24 Scalpel]. This solid fuel missile carried ten MIRV 550 kt warheads and had a range of 6,000 miles. The missile had a circular error of probability of 150-250 metres.
A missile launch train was composed of three locomotives, a generating power car, a command car, a support car, and three missile launch vehicles. The trains were difficult to distinguish from ordinary rail traffic. The trains were based in sidings in Bershet, Kostroma, and Krasnoyarsk and dispersed when things got tense.
The trains could cover up to 600 miles per day and be dispersed over more than 50,000 miles of track. It is clear that the trains, if given the chance to disperse from their bases, would have been very hard to find. It is also clear that if only one of the twelve trains was able to fire its missiles the resulting 30 half megaton bursts could have seriously damaged an enemy.
After 2000 the 36 rail-based missiles were also gradually withdrawn from service, with the last 15 decommissioned in August 2005. One train remains in a museum [see above].
In the 1950s the USA had had plans for 30 trains, each with three Minuteman missiles but the plan was scrapped on the grounds of cost.
US Peacekeeper system
In 1986 the USA planned a system of 25 trains, each with two Peacekeeper missiles. These trains would have two locomotives,two security cars, two missiles cars, a control car, a fuel car and a maintenance car.
The trains would have been stationed in shelters at air force bases throughout the USA and dispersed if an attack seemed imminent. Each train would have had a crew of 42 people—including the train commander, four launch control officers, four rail road engineers, one medic, six maintenance personnel, and 26 security police. The Peacekeeper missile had a range of over 8,000 miles and could carry up to ten MIRV 300 kt warheads. The plan was scrapped before any trains were deployed.
New Russian System
In December 2013 RT reported that Russia is considering developing a new rail based launch system for strategic missiles.
“Russia’s Strategic Missile Forces are preparing to revive railroad-based missiles and counter the US’s Conventional Prompt Global Strike concept. A blueprint of the modernized “nuclear train” will be presented in the first half of 2014.
General Karakayev compared a potential power of a “nuclear train” with several missiles to a division of stationery silo-based intercontinental ballistic missiles.
We see the future missile as solid-fueled, with multiple warheads – with RT-24 Yars as a prototype. We are talking of modifying missiles that are to weigh 47 tons. To compare, a missile in the old nuclear train weighed 110 tons,” Karakayev said.
Within the framework of the START-II nuclear arms reduction treaty with the US, signed by President Boris Yeltsin and his US counterpart, George H. W. Bush in 1993, the SS-24 Scalpel system was decommissioned and all launching platforms were destroyed by 2007.
The ‘New START’ treaty signed by presidents Dmitry Medvedev and Barack Obama in 2011 does not limit the use of railway-based systems, so in 2012 Russia reconsidered development of a new version of a railway-based strategic missile system.
One year later, Russia’s Defense Ministry announced the new railroad missile system would be developed by the Moscow Institute of Thermal Technology – the same institute that developed the sea-based Bulava nuclear missile for the latest generation of Borey-class submarine strategic nuclear missile carriers. The Institute is expected to present a blueprint of the system within the next six months.
The project is aimed at countering the threat posed by the US Conventional Prompt Global Strike concept. This concept implies destroying stationary targets with hypersonic missiles armed with conventional warheads in any part of the planet within an hour of receiving an order.”
Update January 2015
From this Russia Today article
A Russian military source outlined the capabilities of Barguzin strategic missile trains. The country may roll out five such disguised mobile launch platforms each carrying six RS-24 Yars missiles in five years.
A ‘nuclear train’ is a mobile platform for transporting and launching strategic nuclear missiles. Similarly to nuclear submarines, such trains are hard to wipe out in a pre-emptive strike because of their mobility and ability to be disguised as regular freight trains.
Like its predecessor, Barguzin’s carriages carrying missiles would be disguised as refrigerator cars. But since a Yars missile weights roughly half of what a Molodets missile did, the cars would not need reinforced wheel-sets to carry the load. This would make the trains harder to identify from the ground.
The weight difference also means that a single nuclear train would be able to carry more individual missiles. According to designs of the Moscow Institute of Thermal Technology, the weapon platform’s developer, each Barguzin would be able to tow up to six Yars missiles, the source said.
The destructive potential of the new platform would probably be smaller than that of its predecessor however. Molodets missiles had 10 MIRVed warheads with a total yield of 5.5 megatons. Yars reportedly has four warheads with a total yield of between 0.4 and 1.2 megatons. The more advanced Yars, however, is more accurate and has greater range.
The map below is from NUKEMAP by Alex Wellerstein. It shows the effect of a single Yars missile on Washingston.
The outer orange ring shows the thermal radiation radius. Anything out in the open at the time of impact, including people, would catch fire. NUKEMAP estimates the casualties at 281 thousand dead and 261 thousand injured.
A surface burst [fireball touches ground] would produce the fallout shown below.
Since the Yars missiles on each train will carry a total of 24 missiles it would be possible for a single train to repeat the above on another 23 US cities.