The armored train is a functioning vehicle and special weapon of the Red Line, utilized as an incredibly powerful battering ram.
Salvaged from an unknown tunnel or station and built up with a massive amount of steel, the armored train stands as the single most dangerous weapon of war in possession of the Red Line. Despite this, it remains relatively inactive and unheard of for most of Metro Last Light. It is a set-piece item for the opening of the level Revolution, where it is seen being constructed, and is mentioned in passing by Andrew in Regina but is not used and not vital to the plot until the final wave of enemies in D6. The armored train is possibly the answer to Rangers fortification of D6 and the "Panzers" used by the Nazis. In its brief last appearance, it is the deciding weapon that cripples the Rangers by destroying D6's platform - who had previously killed several dozen soldiers of the Red Army, a tank, as well as a shield and flamethrower unit. Though it is obviously destroyed in the C'est la Vie ending to Last Light, what exactly happens to it in the Redemption ending is unknown, though it is possible that the train was rendered useless by destroying the platform.