The biggest challenges facing workers were low pay and difficult (and even dangerous) working conditions.
Mechanized industry was dangerous. There were all sorts of machines running and very little attention was paid to safety. Therefore, there were many more workplace injuries and deaths than we would tolerate today.
Labor was also quite cheap. There was a huge supply of laborers, in part because of the tremendous increase in immigration during this time. The jobs did not tend to need a great deal of skill and so there was no reason for employers to pay high wages. These were the two biggest challenges facing the workers.
The scale of industrialization the country was experiencing during the latter half of the 19th century fundamentally transformed the economy from a primarily agrarian one to an industrialized one with the rise in factory jobs a defining characteristic. While factories provided ample employment opportunities, they also were fraught with new hazards to workers handling sometimes complex and frequently dangerous machinery. In addition, work hours, which were unreasonably long in the fields of agricultural sector employment, were even worse in the poorly-ventilated factories. Workers were subjected to long hours, few days-off, and often hazardous conditions. Additionally, child labor was a major problem, especially in larger cities where factories were abusing children with long hours under the same unsatisfactory work conditions as their parents. In this context, the rise in the influence and power of labor unions was inevitable. The long hours, dangerous working conditions, shortage of paid sick and vacation days, and sometimes physically and emotionally abusive management practices that contributed to the dismal conditions under which many workers labored all combined to give rise to the movement to organize labor. The late 19th Century, then, witnessed that growth in the scale and influence of labor unions, most notably the American Federation of Labor, established in 1886, which succeeded and built upon the success of the Knights of Labor, which had started in 1869 as a secret society dedicated to forcing change in existing work conditions on railways, in coal mines, and in other hazardous occupations. Throughout the remainder of the century and into the next, labor unions continued to grow in power, although not without significant resistance from business owners who resented the presence of labor organizers.