factory towns
The word means "Three towns": there were probably 3 towns on the site in close proximity to each other. There are towns called Tripoli in both Lebanon and Libya.
Population growth and migration
Early factory towns were unhealthy,because conditions in factories were usually unsafe due to the lack of regulation on equipment or the factories themselves.There was no labor laws to protect young workers from getting injured on the job.
towns are many pollution in factories,vehicles etc,etc .
help me
Cape Otway lies to the southwest of Lorne and Apollo Bay.
A group of factories could be called an industrial complex or industrial park.
Diamonds made in factories are called man-made diamonds.
Hanover and Shrewsberry, Pennsylvania are towns that are close to Baltimore and D.C. Littlestown, Pennsylvania is another town that is close.
Cities and towns each have their own plots of land set aside for factories.
Railroads
I think you are referring to a "Megalopolis"