The Army of Republika Srpska operated a train that was ambushed and destroyed in October 1992 near the town of Gradačac by Bosnian Muslim forces that included a T-55 tank.

The Croatian Army deployed a two-wagon armored train built in Split with a shield composed of two plates, one 8mm and the other 6mm thick, with a 30–50mm gap filled with sand between them.

The first wagon train of the Krajina Express was made of a General Motors diesel locomotive (JŽ 664-013, now HŽ 2062 055) and two cars by local railroad workers at Knin.

[3] Following the improvement of the protection with the addition of armor plates, the train provided fire support on the railroad between Knin and Drniš.

[4] The train provided support during the struggle for Škabrnja, where the unit was involved in an attempt to destroy an ammunition dump in Zadar by pushing a wagon loaded with 3,650 kg of explosives and five tons of shrapnel through the Benkovac–Zadar railway line.

In the last days of May 1993, the train was to be involved in Operation "Maslinova grana" (Olive branch), a Serb attempt to break into the Croatian defenses along the Adriatic coast south of Zadar that was eventually called off.

[6] One of the last and best documented actions of Krajina Express were a number of fire support missions along the Una river during the Siege of Bihać,[7] on 1 December 1994.

Later on the day, one wagon was hit by a 9K11 Malyutka missile, which pierced the armor shield, but the rubber protection deflected or absorbed the blast.

[4] The following year marked the definitive configuration of the armored train, when the 76mm gun was supplanted by an American M18 Hellcat tank destroyer.

[8] During the siege of Bihać three additional wagons were hooked ahead of the formation, in order to trigger any mines planted on the railway.