An armored train is a railway train protected with armor. Armored trains usually include railroad cars armed with artillery and machine guns. They were mostly used during the late 19th and early 20th centuries, when they offered an innovative way to quickly move large amounts of firepower. Most countries discontinued their use – road vehicles became much more powerful and offered more flexibility, and train tracks proved too vulnerable to sabotage as well as to attacks from the air. However, the Russian Federation used improvised armored trains in the Second Chechen War of 1999-2009.
(more on Wiki HERE)