In England, the poor and peasants lived off what was called The Commons. This was royal land but they didn’t have much use for it other than foxhunting, so they didn’t care. People had enough to eat and often made a lot of their stuff or bought it from nearby tradesmen. There was a small capitalist economy made up of selling agricultural produce, meat, and mostly the small tradesmen, most of whom didn’t even hire labor. There were hardly any hired laborers because everyone had all they needed.
The capitalists decided that they needed to develop a capitalist economy. They had a problem. No workers. All of the workers were living off the land doing fine on their own. The capitalists would have to drive them off the land, proletarianize and impoverish them in large cities, where they would make up the reserve army of labor Marx’s discusses.
So the Commons was fenced off. The people lost all their livelihood because they no longer had any land to live off. They moved to the cities as an impoverished, downtrodden, often starving proletariat, where they formed large miserable slums. Crime rose. The capitalists starated building factories in the cities. With this newfound reserve army of labor, the capitalists now had captured workers who had their livelihood tied to their job at the factory. The capitalists waved the threat of impoverishment and starvation over anyone who complained.
A similar thing actually happened in the American West and in fact this was how capitalism in the American West actually developed, believe it or not. Herders versus farmers wars, common in the West and still in many parts of the world (Sudan, Northern Nigeria) are similar in that they also involve driving farmers off the land but also quite different as the land is taken over to grazing by herders. But now this new landless class or former landholders was proletarianized and stuck as a reserve army of labor for the development of capitalism in the West.
A similar thing was done with the railroads. The government was getting very worried about all of the people who were just living off the land on their own. At first, the state gave people small plots because this helped in the theft of land from the Indians which was essential for the development of the nation.
But by the late 1800’s this had become a liability. So vast tracts of land were given to the railroads before homesteaders could snap them up. In this way, the development of rural self-sufficiency in the countryside could be slowed and the creation of a large impoverished, hungry class of workers could form in the city slums to serve as the reserve army of labor for the development of capitalism in the West. Until recently, Southern Pacific had large landholdings in the West.