Dallas Fire Tiller HazMat 3 

I understand wanting a truck and trailer for this purpose, since a straight truck of the same volume would be too long to be maneuverable in some situations... but a tiller seems like an extreme solution. A conventional truck and conventionally hitched trailer would turn as tight and would be cheaper and easier to build, probably with more usable payload space and without requiring someone to drive in the tiller position. The trailer could even be a tandem with automatic steering on the trailing axle so its tires would track close to the truck's rear tires. It could also make sense to share a standard tractor configuration with other apparatus (presumably ladders), but this is not a standard tractor.

It's unfortunate that all of the images (photos and drawings) are shown distorted in this video - they're stretched horizontally. That really makes it hard to understand the proportions of the rig, and it's surprising to see in a recent (this decade, or longer) video. Did Siddons-Martin provide this material this way? I don't see anything on their website that looks like this, either such low resolution or distorted.

No 55 gal overpack drum?

Thanks for the shout out!! @woods_wood_shop