Modern-day armored train in service with the Russian Federation, apparently still viable as a weapon there due to the sheer size of the country.
I feel like guided missiles would have an excellent home on an armored train. The long range and self guidence really make up for the trains limited aoe. While the train’s speed and defensibility can put the missiles where you need them quick. The trans Siberian railway takes about seven days to traverse, which is dismal compared to jets but the train can hold much more ordinance and is still much faster (and more reliable) than roads.
The static nature of the rail makes it a pretty defensive platform, but it’s an interesting marriage of old and new.
Allow me to introduce you to the RT-23 Molodets (NATO reporting name SS-24 Scalpel)
Deployed in 1987, each missile carried 10 MIRVs with 550kt warheads. The type was withdrawn to comply with START II in 2005.
The US was working on a similar idea, the Peacekeeper Rail Garrison, at around the same time, but the project was canceled at the end of the Cold War.