NYC road construction

My group asked the road worker what they were doing.  Two really nice workers explained they were replacing the electrical work.  They also showed us the steam pipe, the water main (which was built in 1884 and is still used today) and the gas line. All the lines are just inches below the road bed as the subway ran just 4 feet under the road. So all that infrastructure was housed in just 3 feet.  There were big buckets of dirt that they will use to fill in the gaps between all the pipes.  They will repave the road when the work is done.