What are three events that occurred in Europe and Asia that led to change during the Middle Ages

With the california gold rush and the opening of the west came an increased interest in building a transcontinental railroad the first chinese were hired in 1865 at approximately $28 per month to do the very dangerous work of blasting and laying ties over the treacherous terrain of the high sierras in the beginning was slow and conquer the many embankments, the chinese workers used techniques they had learned in china to complete similar tasks. they were lowered by ropes from the top of cliffs in baskets, and while suspended, they chipped away at the granite and planted explosives that were used to blast tunnels1.* 11b this passage reflects workingefforts and conditions of which corporation? a.the transcontinentalrailway line b.the union pacific company c.the central pacific company d.the norfolkwestern company