The Bobcat with the pecker just breaks through the tarmac and concrete and loosely the dirt then the vacuum sucks it all up.
The new plastic main is inside the old cast iron pipe, then they disconnect each house and inject expanding foam in between the old and new, smash the old cast iron pipe and fit a saddle.
the service pipe to the house is the same with a plastic pipe inside the old pipe, then just connected to the meter.
all done with live gas so no smoking while they do it.