truly amazing engineering – any video of the “after” tunnel? was the truck modded in house or did you purchase the roller system somewhere? Impressive system, like the way you thought it all through. I was also impressed that even with the back fill not compacted that the machine didn’t increase the thrust to the point that the springing spread apart. But then, the voussoir’s are probably over specified and with the cost of the raw materials why the bloody hell not !
