Conversation so far:
How did Andrew Carnegie's Keystone Bridge Company come about?
The Keystone Bridge Company, founded in 1865 by Andrew Carnegie, was an American bridge building company. It was one of 28 companies absorbed into the American Bridge Company in 1900.
What had Andrew Carnegie been doing previously?
In spring 1861, Andrew Carnegie was appointed by Thomas A. Scott, as Superintendent of the Military Railways and the Union Government's telegraph lines in the East.
What was Story Farm?
The Story Farm consisted of 501 acres, all but 100 acres being on the west side of Oil Creek, Venango County, Pennsylvania. James Story, settled there in the early 1800’s.
How much did Andrew Carnegie's Keystone Bridge Company make from the oil?
In one year, The Story Farm yielded over $1,000,000 in cash dividends, and petroleum from oil wells on the property sold profitably for Andrew Carnegie
What other items were Andrew Carnegie's Keystone Bridge Company making?
Andrew Carnegie's Keystone Bridge Company was also making iron products, such as armor for gunboats, cannons, and shells, as well as a hundred other industrial products
What else was the Keystone Bridge Company producing?
Carnegie worked with others in establishing a steel rolling mill, and steel production and control of industry became the source of his fortune.
What else was Andrew Carnegie's Keystone Bridge Company doing to grow the business?
One of Andrew Carnegie's two great innovations was in the cheap and efficient mass production of steel by adopting and adapting the Bessemer process.

Question: What did he do after that?
Self-contained rewrite: What did Andrew Carnegie do after that?