The transcontinental railroad did this in two major ways. First, it helped to stimulate the steel industry. The demand for all those rails needed to build the railroad and for the cars that ran on those rails helped cause the steel industry to boom. Second, the transcontinental railroad created a huge market that allowed industry to expand. It allowed factories to get raw materials from anywhere in the US and sell their products to anywhere in the US. By doing these things, the transcontinental railroad allowed the US to become an industrial power.
The transcontinental railroad provided the basis for the growth of industrialization after the Civil War. The building of the transcontinental railroad required the use of many machines and many resources. The building of the transcontinental railroad alone helped industries grow.
The transcontinental railroad also helped people move to the west. It became easier to move westward as a result of the railroad. As people went to the west to farm, to mine, or to raise cattle and sheep, the transcontinental railroad made it easier to ship products to the west. As the west grew, the demand for industrial products increased. Since it was easier to get people and products to and from the west, industries were able to make more products and sell them. Eventually, industries began to expand their facilities to the west so they could be closer to the people living there. The transcontinental railroad made it easier for these businesses to expand to the west.