Railway guns were introduced during WWI, and were often repurposed coastal artillery pieces or naval guns, the size of which were otherwise unfeasible for normal military use. These pieces were normally too large to be of any practical use to an army, but once WWI settled into fighting from fixed positions larger cannons capable of demolishing bunkers was required. Since these guns had to be ferried and supplied by railroad, which in itself went all the way to the lines, the logical solution was to construct the gun carriage itself on a railroad cart. This way the guns could be (relatively) easily moved and transferred where needed.

While some railway guns remained by WW2 (primarily fielded by the Germans), they were of limited practical use and were non essential due to weight and complexity, while the strategic bombardment role was primarily filled by aircraft.

Notable guns on the extreme end include the Paris Guns which were built to shell Paris towards the end of WW1 (with limited success) and the WW2 Schwerer Gustav, which was initially constructed to bombard the Maginot line, but ended up seeing use in the Siege of Sebastopol.