Many in the middle lack the skills to move up and are pushed towards the low-wage end of the economy. Machinists and tradesmen become cashiers and call-centre workers.
His talent as a machinist and fireman earned him commendations, but he occasionally found himself in minor trouble and never rose above the rank of seaman.
They had little money, so they moved to Wisconsin and lived with Paul's parents for a few years, then headed for Indiana, where he got a job as a machinist for International Harvester.
So George Stevenson, born in 1781-ish, son of a coal miner, just went to work with his dad in the colliery as a teenager, 14 years old, just worked his way up because he was adept, he was a good machinist.
A machinist, by the way, is essentially a trade person that specializes in making metal parts, really precise parts that go in everything from cars and airplanes to tools and medical devices.