Final answer:
Railroad owners and government workers benefited from the prosperity of the late 1800s, while coal miners and child laborers continued to endure harsh conditions for low pay, despite being crucial to the economy.
Step-by-step explanation:
The prosperity of the late 1800s in the US largely benefited those in positions of ownership or high management within the burgeoning industries. Those who would have seen the most benefit from this prosperity would likely be railroad owners and government workers.
Railroad owners profited enormously from the expansion of the transportation networks and the increased flow of goods and people. Government workers could have benefited from the increased revenues flowing into public coffers that helped stabilize and possibly enhance their positions and livelihoods.
In contrast, coal miners and child laborers, while integral to the economic machine of the time, typically endured harsh working conditions for low wages, and thus, did not experience the economic prosperity to the same degree as the owners and upper management. Coal miners faced dangerous and unhealthy work environments, and child laborers were subject to exploitation, with little protective regulation in place to ensure their welfare.
The economic growth fueled by the transcontinental railroad and related industrial expansion exacerbated the gap between the rich and the poor and between those who owned the means of production and those who labored. While some individuals moved into the middle class, the majority of workers, including coal miners and child laborers, remained in difficult circumstances.