There are several and they all cross the continent. Which continent depends on which railroad you are referring to.
No, he didn't precisely help finish the railroad, although he did help fund it. It was Leland Stanford who really finished the railroad.
1869
City Point Railroad ended in 1847.
City Point Railroad was created in 1836.
Traverse City Railroad was created in 1871.
Traverse City Railroad ended in 1917.
Utica City Railroad was created in 1862.
Utica City Railroad ended in 1866.
Brooklyn City Railroad was created in 1853.
Elkhorn City Railroad Museum was created in 1990.
New Irish immigrants laid much of the tracks east of Utah. Chinese immigrant workers provided a great deal of track labor west of Utah. People from every part of America worked on the railroads.