I would speculate that the mushroom is just a very heavy mass that the engine lifts and drops. I'm going to guess it's 1000 tons and the engine is a modified crane. It lifts it pretty quick, so whatever is is, it's powerful. (The reason I don't think its a piston is because of the block and tackle , but that could be for something else entirely).

Time lapse was, a frame a day or so. The cranes are designed to be taken down quickly. Less than a day in most cases. At that framerate, they just disappear.

what happened to the cranes?

Not just you. Also looks like a prototype being lifted by a crane in some shots. The propellers look too small to lift that mass.
I was also suspicious that they had so much footage under various lighting conditions. The twilight shots especially, which are dangerous conditions to fly under. Could be we're wrong, and just be artful CG for the sake of a fundraising video?

Crane: Nothing to see here. Move along.

Gator: Feckaff.

Amazing video, some of that looks super dangerous, like if he got a foot caught on that crane or if the two gliders got their chutes tangled.

Those ski runs look sooooo fun!

I looked it up last time around, and although I've never seen one apparently there are plenty of Opiliones here, but the ones we call daddy longlegs are Pholcus phalangioides, the spiders that live inside (and eat our less cuddly spiders). They aren't native to Australia, they were accidentally introduced from Europe.

I wouldn't personally describe either Opiliones or Crane fly as daddy longlegs, only the daddy longlegs spiders.

Reference - https://australianmuseum.net.au/daddy-long-legs-spider

Well this is confusing, here in the UK we call it a Harvestmen and a Daddy Longlegs is a Crane fly.

I don't think karma is applicable, the guy couldn't see the massive crane beyond the truck cab, and there's no reason for him to lean forward and check because massive cranes on the back of trains are not a thing.

I've seen expert commentary on this. Buildings do NOT just pancake like that. Clearly an inside job and somebody had explosives inside that building already. The crane is just a cover story. Truth!

Your video, Crane Collapse During Bridge Construction In Italy, has made it into the Top 15 New Videos listing. Congratulations on your achievement. For your contribution you have been awarded 1 Power Point.

Maybe I watch too many FailArmy videos but it seems like cranes fail as much as they work.

Crane fell? Steel can't melt at that temperature. Fake news! Someone blame Obama, quick!

Man, so spooky. That place would be a really awesome setting for a video game. Can you imagine stalking through that wilderness, dodging mutants and bandits beneath those clear skies? I can almost hear Pripyat calling me.

(seriously, I think I recognized some scenes from the games in those videos... isn't that bit in the beginning with the cranes identical to the starting map of "Call of Pripyat"?)