All of that with virtually no automation as well. Just sheer brute force of labour: Machinists, welders, forge operators and their tools.

Kind of depends on your definition of automation, I suspect many of those jobs were using much more advanced tools than their grandparents would have. If I were to build a fence tomorrow I'd be using a nail gun and bench saw to automate most of the hard work, as little as a few decades ago I wouldn't have had those tools.