The Jernbanekanon nummer 1 (JK-1), or the "Eeobroht Gun” as it was codenamed during development, is a railway-transported heavy cannon designed for siege purposes and for mobile coastal defense purposes, as well as being a source of national pride and deterrence.



The JK-1 was commissioned after it was determined that permanent coastal gun positions were too vulnerable to enemy first-strike attacks. The JK-1 is intended to perform a dual role: 1.) coastal defense; and 2.) siege bombardment. After a clandestine round of inquiry, on December 16, 2000, the Kongsberg Defense Industries was selected for the contract. The design specifications required by the military was for a large calibre ETC cannon (350 – 400mm calibre) to be transported and operated on the normal railway network, and to be able to hit mobile targets at distances of at least 180 kilometers away. It also had to be crewed by a maximum of 200 personnel. With these design specifications in mind, the team got to work.



Taking the lessons learned from railway cannons designed in the past, the engineers at Kongsberg decided on a base designed around two smaller carriages of four wheel pairs each for holding the main base, which was attached to both carriages with one in each end. This would allow the JK-1 the manoeuvrability required to operate on the Cottish railway network, and to distribute the massive weight correctly. The rail gauge of the wheel pairs are the Cottish standard, namely 1,600 mm.

The cannon base is armoured with a classified amount of armor, but designers claim it is sufficient to withstand all small and medium-caliber gun and cannon fire, and even RPGs and several other types of anti-tank weaponry.

The base is also equipped with extender legs for increased stability during firing. These legs are extended out three meters and firmly placed into the ground, supporting the weight of the massive railway cannon when it fires.



The first thing the designers needed to decide on was what kind of armament they would put on the JK-1. After a number of feasibility studies, computer simulations and other tests, they finally decided on a modified M206 Medium Caliber Cannon designed for use on naval battlecruisers. This cannon had a calibre of 380mm and fired an 800-kilogram projectile. The battlecruiser versions were designed around two or three cannons, so the engineers at Kongsberg had to redesign the M206 to fit onto the carriage. What they ended up with was the M206A3 380 MM/60” Medium Caliber Cannon (Railway). The M206A3 MCC® weighs in at 100 tons, and has a length of 22.8 meters, of which the bore is some 19.63 meters long. It is also fitted with a muzzle brake, reducing the recoil significantly. With a rate of fire of approximately one round every five minutes if required, the JK-1 is a relatively rapid-firing railway cannon.

The barrel of the M206A3 is elevated through the use of an electrically powered, hydraulically operated lifting device near the breech. The lifting device can handle up stresses of up to 150 tons, and is capable of elevating the cannon up to 65 degrees.

The M206A3 fires a 800-kilogram projectile at a speed of 1,050 meters per second out to ranges of sixty kilometres when firing an unguided high-explosive shell, or out to an impressive two hundred kilometres when firing the standard shell, which is a smart GPS-guided shell which is able to be guided in-air, enabling it to be a truly accurate weapon of war. This amazing ability is a modification of the XM982 Excalibur guided artillery projectile, with a circular error of probability (CEP) of some 10 meters – more than sufficient as it carries 500 kilos of high-explosives. The JK-1 carries seven shells in the ready to fire magazine, and an additional fifty in the ammunition car.

Of course, the designers at Kongsberg also thought of the possibility of the JK-1 being required to defend itself. Therefore, they added six Browning M2HB 12.7x99mm heavy machine guns and two FIM-92 Stinger short-range surface to air missile launchers to the JK-1. 1,000 rounds are available for each of the six machine guns, and make the JK-1 more than able to defend itself against ground attack.



The JK-1 is equipped with an Electrothermal-Chemical cannon, which means that it requires electricity to make the process of firing the shell possible. Realizing that external power sources may not always be available, the designers at Kongsberg came up with the possibility of fitting an electrical generator on the JK-1. After some studies and simulations, they came to the conclusion that it was indeed possible, and so they did just that. A DABB 2.2 megawatt diesel-powered electrical generator was fitted onto the rear carriage, and electrical wires were worked into the mounting that connected the carriage and the actual base. The generator consumes fuel at a rate of thirty-nine litres per hour, and powers not only the cannon, but also the other electrical systems on the JK-1.



The designers at Kongsberg realized that in this modern times, the cannon would require the actual fire control electronics on the JK-1 itself instead of having it in another car like in the past. To achieve this, the fire control electronics had to be rugged and shock-proofed as the recoil of the cannon would be rather substantial. So, with shock-proofed electronics based on that of the original M206s found in the fire controls of battleships and battlecruisers, but modified for ground-operations, the fire control systems were tested to the breaking point, then taken back to the labs, refined and tested again. Finally, the fire controls met the specifications required and the JK-1 had its electronics.

The JK-1/E-47 Fire Control Suite is fitted with among others GPS and inertial navigation systems and a powerful digital fire control and ballistics computer, and is capable of tracking and calculating ballistic trajectories for up to sixty targets at once. It also features the Encrypted Two-Way Data Uplink system used by all major Cottish military machines and units. This allows the JK-1 to receive target coordinates and other vital information required to destroy the enemy from external sources, such as forward observers, Unmanned Aerial Vehicles and RADAR sites, and feed that target data into the warhead. It is shock-proofed to withstand continuous fire from the M206A3, and is hardened to withstand Electromagnetic Pulses. The JK-1/E-47 is powered by the DABB generator mounted on the JK-1. The JK-1/E-47 can be remotely operated from a dedicated command and control car if needed to.



The JK-1 system is crewed by a total of one hundred thirty-one personnel. While the process of operating the JK-1 is far less complicated than on past models, it is still crew intensive as the shells need to be brought from the storage and loaded into the breech manually.

A crew of forty is required to operate the M206A3, operating the lift required to raise the shells from the armoured ready to fire magazine underneath the breech, and to restock the ready to fire magazine using the lift on the rear of the cannon to load shells from the ammunition car and into the magazine. Three men man the JK-1/E-47 fire control suite in an armoured and sound-proofed compartment in the front of the car, operating the cannons electronics. Six men are needed to operate the two locomotives that haul the system. Twelve men are required to man the command and control car, where the decisions are being made and relayed to the JK-1. A security detail of forty infantrymen are also with the JK-1, forming the close protection perimeter whenever the train isn’t moving. Finally, a logistics crew of thirty men are responsible for keeping the train and its crew fighting fit, hereunder the chefs, maintenance personnel and supply personnel.

The layout of the train set is as follows, and is listed in the default arrangement: Two locomotives in front, three supply cars, the JK-1 car, two ammunition cars, an electronics car (houses the computers and satellite dish), the command and communications car, five sleeping cars, galley & mess car, and caboose. Total: 2 locomotives, 15 cars.



Car Length: 31.60 meters (total); 8.50 meters (car)
Car Width: 2.50 meters
Car Weight: 260.00 tons
Gun Length: 22.80 meters
Gun Diameter: 380 MM
Gun Weight: 100.00 tons
Shell Weight: 800.00 kg
Shell Range: ~60 km (unguided), ~200 km (guided)
Crew: 40 (gun); 131 (system)
Cost: $130 000 000 (gun); $500 000 000 (system)
Operating Cost: $7 000 000 per annum (gun); $60 000 000 per annum (system)