Nuln Siege Cannon

"Jurgen Von Grissen's Steel Leviathan of absolute and indiscriminate devastation."

Jurgen Von Grissen took another sip of his coffee and grinned cheerfully to himself. The massive bulk of the Siege Cannon lumbered awkwardly forward, white smoke puffing from the Steam Tank pulling it. Thank Sigmar they'd finally cracked the key to making new Steam Tanks just before the dark years. Without one of the lesser workhorse models, moving the Siege Cannon would be basically impossible. 
Beside him, General Olafssohn was making a face. 
"I don't want to be a killjoy, Jurgen," Olafssohn said carefully, "but I'm pretty sure His Majesty asked us to retake the Empire, not flatten it."

Von Grissen chuckled. 
"Oh, do stop worrying Sigfried. It'll be strong enough to effect a wallbreach, but with the right calculations it won't do much more than that."
That didn't seem to reassure Olafssohn much. He glanced sidelong at his old friend. 
"You... erm... you did design this thing to throw shells over the Auric Bastion, didn't you. And the Auric Bastion was..."
Von Grissen beamed. 

"Three thousand four hundred feet tall, give or take a foot. Don't worry, Sig. Jorge helped me to devise some of the settings."
The reference to Jurgen's Gold Wizard son didn't really help, but Olafssohn had the good grace to keep his face neutral. Von Grissen enthusiastically pointed to the arcane housing of the vast gun barrel as it trundled past. State troops were hurrying to get out of the way, no easy task in the crowded streets of Averheim. 

"See those candles and all those odd bits and bobs? That's all part of a Chamon Trap, or so Jorge calls it. When the gun fires, the Trap activates, absorbs the recoil and rechannels the energy back into the barrel. Keeps it stable and stops it overheating."
Olafssohn grunted. 
"Have you tested this thing?" he asked, "you didn't get a chance before the Auric Bastion came down, as I recall..."
Von Grissen's smile widened. 
"That's what we're off to do now. I'm fairly sure it won't explode..." 

I've had this idea knocking about in my head for years. One day a while back I roared in holy wrath 'just get on with it'.

Some bits of it are fairly self explanatory. The Steam Tank Thunder Bearer is simply a regular ST with the roof left off and a couple of engineers put in there (after painting them). The steel bars hooking it to the Siege Cannon are just some thin dowel (they wouldn't be required to hold any weight). The feel I was going for is that of an old-school traction engine.

Now, the cannon itself is a bit more complex. The main gun itself is a Forgeworld Siege Bombard which was originally for my Imperial Guard, until I decided to totally revamp said Guard. The sides are from a War Altar, pinned to the gun (that barrel is much too heavy to just glue). The floor of the Siege Cannon is actually two War Altar floors side by side, and the wheels also from the War Altar.

I decorated the barrel with some bling from the various Empire kits (Fortified Manor, Greatswords, Flagellants and maybe some others).

The front of the carriage is the sticking point: I made it from random spare model train parts that I scrounged from my friend Tom. I can't for the love of god remember which kit it was.

I'll be writing up rules for this in a chapter of Age of Rebuilding that I'm calling 'The Steel Parade of Nuln'. This will include the Siege Cannon, Lord Engineers, and the aforementioned Tom's Knights of the Burning Stone. You will not believe how awesome his conversions are!

Anyway, plug over! Yell if you have any questions.