Gustav and Dora Railroad Guns, the largest ever used in combat

I wonder what the scale is for this model.

SlashGear, Image by Paul Hermans via Wikimedia Commons | Cropped and scaled | CC BY-SA 4.0
"THE BIGGEST GUN EVER USED IN COMBAT: GERMANY'S SCHWERER GUSTAV"
It was designed to defeat the Maginot Line and had the requirements to "bust through walls made of three feet of layered steel or 23 feet of reinforced concrete....The entire rig was over 150 feet long, 40 feet tall, and weighed nearly 1,500 tons. The barrel alone was 100 feet long and had a 31-inch-wide bore that fired two different 80cm (800mm) caliber shells measuring over 2.5 feet wide and 12.5 feet long. The five-ton high explosive round carried over 1,500 pounds of explosives, made an impact crater almost 30 feet wide and 30 feet deep and could hit a target downrange nearly 30 miles away. The heavier seven-ton armor-piercing round contained just over 550 pounds of explosives and had an effective target range of around 23 miles. Given the size of the shells, it could only fire 14 projectiles a day....Gustav cost an estimated 10 million German Marks to build, was used twice, and fired less than 100 rounds. While it was the biggest gun used in combat, it was not the biggest gun ever built. That claim to fame lies with "Little David," a 36-inch (914 mm) cannon built by the U.S. Army to use against Japanese bunkers. Fortunately, the Japanese surrendered before it was ever needed."

WeAreTheMighty
"The Schwerer Gustav and its sister gun Dora were the two largest artillery pieces every constructed in terms of overall weight (1350 tonnes) and weight of projectiles (15,700 pounds), while it’s 800mm rounds are the largest ever fired in combat. The guns also had a range of over 24 miles. The guns were originally designed to be deployed against the French Maginot Line though the Blitzkrieg rendered that mission obsolete. Instead, the guns were deployed to the Eastern Front against the Soviet Union. The Schwerer Gustav entered combat during the German siege of Sevastopol in June 1942. The gun was manned by a crew of over 1400 men, 250 to assemble the weapon, two anti-aircraft battalions to protect it, and the rest to load and fire the weapon. Dora was set up to be deployed against Stalingrad, though it cannot be confirmed whether it fired against its target or not. Both guns remained on the Eastern Front but were not used in combat again. They were destroyed in Germany to avoid capture by the advancing allied armies."

The Steam Channel posted
Peter Shaw’s 1/6 scale Scratchbuilt Dora.

Alan Ashworth: This gun was bigger the both Annie and Bertha. It operated two sets of tracks. The one in the picture is 1/6 scale that is same scale as the old GIJoes 12'' ones. Dora was the name of the wife of the president of Krupp.

Ingmar Frans Sandberg: It's as second world war cannon, it was used on the coast l line for invasion, it was big enough to put a battleship on the bottom of the ocean, to bad for the Germans they built most of them on the wrong locations.

Brian S. Franchise: The actual gun was two stories high. A shell from that was taking out whole towns. But it took too much manpower, was visible from the air from enemy planes, and could only fire 4-6 shells a day, so they got rid of it.

Steven Anderson: It was an impractical weapon as it also had to disassembled to move it.

[I think some of the commenters mistook this gun for Gustav.]

This was a smaller gun, but still pretty big.

reddit
the_howling_cow provides the caption on the original Signal Corps photo:
"Mammoth 274-mm railroad gun Captured in the U.S. Seventh Army advance near Rentwertshausen easily holds these 22 men lined up on the barrel. Although of an 1887 French design, the gun packs a powerful wallop. April 10, 1945."

Wikipedia, Public Domain released by Allocer
"Schwerer Gustav (black) compared to an OTR-21 Tochka SRBM launcher (red) (which launches projectiles of similar size and range) with human figures for scale"