I think the title makes the point of this list clear; STEEEEAAAAM TAAAANKS (and artillery). The freeguild guard are essentially just cheap battleline fillers – the cheapest available within the greywater fastness allegiance, while everything else plays (at least partially) a role in boosting your tanks and rockets.
The greywater fastness free city allegiance ability is an obvious pick, what with the focus of this list being on the steam tanks and rocket batteries. The ‘punishing bombardment’ rule lets you roll a dice for each WAR MACHINE; a roll of a 6 will let you fire immediately with that WAR MACHINE. Since there’s 5 WAR MACHINES in the list, you’ve got an 83.3% chance of getting free shooting with a single WAR MACHINE in every hero phase.
This short fellow lets you heal 1 wound on a nearby (within 4”) WAR MACHINE with his ‘Engineer’ ability. Also unlocks the use of the ‘I Meant to Hit That One, Honest’ ability on your rocket batteries, since he has the ENGINEER keyword. Since he’s slow as anything with a 4” movement, keep him near your rocket batteries as they’re equally slow.
Alternatively, you could switch the Cogsmith out for a Jade Battlemage to let you heal a unit with lifesurge (D3 wounds healed on a single model if successful; also lets that unit ignore wounds or mortal wounds in the next turn on a 6).
Not as good as he used to be with the older version of his warscroll but still a good and thematic addition to the army. The ‘Arcane Engineer’ ability gives a +1 Hit bonus to ORDER WAR MACHINES wholly within 9”, so he’s best kept as close as possible to either your rocket batteries or behind your steam tanks.
A lovely looking model and a really solid part of the army (a good way to access magic while buffing your WAR MACHINES). Storm of Shemtek and Comet of Casandora provide you with a nice source of mortal wounds while the ‘Portents of Battle’ ability gives you a blanket +1 Hit bonus to any order models.
You could also switch the hurricanum out for it’s cheaper cousin, the Luminark of Hysh, which has a nice long ranged laser (but lacks the mortal wound punch of Storm of Shemtek; though you get some MW’s through Burning Gaze) and trades the +1 Hit bonus of the Hurricanum for a chance for any models within range to ignore wounds or mortal wounds on a 6. As the luminark is cheaper, you could also use this option to let you fit in both a Cogsmith AND a Jade battlemage for even more healing and protection.
If you were playing the FREE PEOPLES allegiance, you’d no doubt want a large unit of these mustachioed fellows; this isn’t the case here – they’re just cheap battleline to fill those slots so you can get on to more important things like STEEEEAAAAM TAAAANKS.
There’s few things more fun than shooting oversized firecrackers at the foe. You might think that hitting a 5+ ia rather poor (it is) – that’s why there’s three sources of +1 Hit bonuses in this list; firstly we have the ‘Rocket Salvo’ ability of the Battery itself – you get the hit bonus if you fire all your shots at the same target. Second is the ‘Portents of Battle’ ability of the Hurricanum, though you won’t be able to keep both the Steam tanks and Rockets in range for a bonus on both if you plan on moving the Steam tanks around a lot. Third and last is the ‘Arcane Engineer’ ability of the Lord-Ordinator. If you’ve kept the Cogsmith next to your rockets, there’s also the ‘I Meant to Hit That One, Honest’ ability that, on a roll of a 6, lets you hit another unit within 10” if you missed your original target. Another nice bonus to the Batteries is that ‘Arcing Ordinance’ does away with the notion of line of sight and lets you fire at unit that aren’t visible to the battery and crew.
If this list was a Sunday roast, the Steam Tanks would be the roast beef itself. You’ve got a fun mechanic in the form of ‘More Pressure’ which lets you gamble on the current state of your tanks; you roll 2D6 (it’s helpful to remember that the average of 2D6 is 7) and if the result is less than the number of wounds sustained, you take D3 mortal wounds. If it’s equal to or higher, you get to re-roll any random values for the model barring the repeater handgun. Alternatively you can heal a single wound on the tank via the commander’s ‘I’ll Fix It’ ability.
If the enemy starts getting too close for comfort, you can charge them and deal D3 mortal wounds (but perhaps it’s best to keep them back a little, given the 30” range of the steam cannon and long rifle, even if it is fun to yell DRIVE ME CLOSER I WANT TO HIM THEM WITH MY SWORD).