For example, he did work on the so-called science of shovelling. He determined that a worker should shovel 21 lb per shovelful so that he could go the longest time. He also coached workers to use their body not their arms to lift. Today we know that sore backs are a big chronic problem, and that sore arms are less serious.
Taylor wrote a large book called The Principles of Scientific Management, which happily is free on Kindle and on Google books. Scientific management is not the management of science, but rather the use of experiments to improve productivity.
Taylor's work is hard to summarize, but three principles:
Some of what Taylor advocates might be called worker training today. That is, if we show people how to shovel, then they shovel better. In the 1890's workers were assumed to know how to do their work, and the bosses often did not.
When I was in business school I admired the idea that studying the work at hand could make accomplishing it easier. I particularly liked taking a detailed approach to relatively simple workplace problems.
Reading Taylor today, social issues problems and class distinction are on every page. Taylor regarded himself as progressive in his day, and he tries to give what he says as a reasonable view. The country, and actually the industrializing world of the time, were all grappling with these issues. It may have taken another fifty years before some resolution is achieved.
More: Taylor writes about "soldiering" which means workers who slow their work-pace deliberately to get paid more or so that the employer needs to hire more workers. Maybe we'd call that goldbricking or featherbedding today. Taylor understood that paying by piece-work only helped so much. He thought his system led to greater productivity, and the ability to pay higher wages which would motivate the workers to have a better attitude and work harder.
Even More: This an excellent web page on early management theorists.