Pittsburgh in PA is known as the Steel City.
The town itself was built off of the steel industry.
Today Pittsburgh is full of cities and suburbs and the hubs of the former steel industry has faded away.
The new big guy in town is the Fracking industry in the suburbs of the city tearing up ground and soil and making large amounts of noise that goes ignored by the townships because they have no control over them.
Both fracking and steel making put pollution in the air but both brings large amounts of money to the residential owners and townships that make it ok for them to put their dirty hands in politics of the town.
Fracking is noisy. Even when it seems quiet, there is still loud noise that always happen in the middle of night.
Freight engine noised that aren’t possible, because you don’t live next to a train track.
Here’s what Steel Mills might look and sound like:
This is exactly what it sounds like. And it’s done in residential areas all over the place.