Did you know about the never-produced French “centipede tank”?

World War II was full of weapon designs that ranged from the innovative to the crazy. From trench-digging tanks (Churchill’s Underground Tank) through aircraft carriers made out of ice to bouncing radio waves off a target (also known as “radar”), the war was full of breakneck technological development that sometimes panned out and sometimes didn’t. One example of a crazy idea that didn’t work out was the obscure, never-built French “assault train,” which crossbred a tank with a centipede.

Practically nothing is known about the assault train’s inventor, Victor-Barthelemy Jacquet, other than his street address in Paris in 1922, and a series of patents filed in France and Britain between the 1920s and 1944. His designs suggest he had a certain amount of engineering knowledge.

His penultimate patent, submitted in 1944 when France was already being liberated by the Allies, was for an armored vehicle that could cross difficult obstacles. It comprised three separate cabins, each with its own tracks and turret, connected by a complex hydraulic system that allowed the cabins to turn independently of each other, and to also “go rigid” when crossing a wide trench or canal. When climbing up an escarpment, the front cabin could be raised then pushed up the slope until its tracks found purchase; it could then help pull up the other sections.

The assault train had some interesting features. The leading cabin’s turret was slanted forward so it could pour machine gun fire into a trench, or shoot forward while cresting a slope. The front cabin was also lower and narrower than the center one, so the latter could shoot forward past it.

The patent makes a vague mention of “liquids, gases, compressed air, etc., necessary for… The defense of the assault train,” implying that maybe it was supposed to spray poisonous, flammable or corrosive substances at the enemy.  Its traditional armament was not described in detail but probably would have contained around 4 machine guns, a 75 mm gun, and a “compressed air mine tube against anti-tank barriers,” whatever that last one was going to be. Bafflingly, the main gun was placed in the rear cabin, and not even in the turret: it would have stuck out directly to the back, aimed by moving the entire vehicle. As far as it can be determined, the assault train would have required a crew of 8-10, a ridiculously high number for something 19-23 ft (6-7 m) long.

Complicated to build, maintain and operate, it’s no surprise Jacquet’s invention never saw daylight. It was filed in 1944, accepted in 1951 and promptly forgotten as just one more of World War II’s many crazy ideas that never took off the ground.