Diesel Creek

Michelle asks: And you really expect to find machines here that can be salvaged?
The four are walking into a valley in a large forested area.
Jack replies: Right now, I'm not even sure this is the place – everything looks so different – but, if it is, we'll have plenty to choose from and a bunch more for spare parts.
James gestures to the side, saying: Look, over there.
He points out a group of very rusty and completely overgrown machines.
Annie wonders: How did they get inbetween the trees?
Jack says: They didn't. The machines came first, the trees grew after. This wasn't a forest back then.
They make their way over to take a closer look.

Jack says: Looks like these were already out of order before they were abandoned.
He turns to Annie and James: This is an excavator. We're looking for a big one like this, maybe a bit smaller, but not as small as that one over there – and preferably without trees growing out of it...
He points to a small excavator that sits askew on a thick tree trunk that had grown through the floor and out the side. Compact excavator? Tiny excavator?
James asks: Why not just use this one? What's wrong with it?
This thing's just done for. Apart from it being a pile of rust, it's missing its tracks, the hydraulics for moving the bucket, and it looks like the inside of the cab got completely dismantled.
They take a quick look at the other machines around them. There is the other, much smaller excavator, a dump truck, a what's the name of that machine with a conveyor belt that sorts large rocks and rubble from sand? , and two loaders. All of them are rusted beyond repair and missing integral parts.

A bit further down the valley, they approach a much larger collection of machines, parked in rows and parted out like the first ones they saw.
Jack says: Welcome to the machine graveyard. If memory serves right, there should be a few buildings back there and one of the main parking lots behind them.
While they make their way through between the machines, Annie asks:
So these machines dug out the dome?
Well... no. That was mostly done using explosives, conveyor belts, and trains. They used loaders to get the stuff onto conveyors but most of the machines here were used in construction after the digging was done.

research that needs to be done: When were hydraulic excavators invented? When did they get the ability to use a jackhammer attachment? When did the cable-driven ones go out of fashion?

missing section

Annie calls the others over to one of the buildings.
Look what I found...
Michelle arrives before Jack and she laughs. He arrives a moment later and peeks inside. There sits a cable shovel, partially covered in rubble from the caved-in roof – rusty but surprisingly intact.
Jack says: That's ... uhhh ... kind of a historical artifact.

missing section

Things that need research: Did early hydraulic excavators have starter engines (what were they called again?) or was that a thing of the past by then?
Events:
-> they take off some access panels
-> they manage to get the starte engine going
-> large engine won't start (why?)