America in the West by far.

Consider that the Far East for Russia is Siberia, which even on a good day, is pretty uninhabitable for people. The Far East does have ports for Russia such as Vladivostok, but you're talking about traversing multiple lengths of America just to get there and the end benefit is minimal - most of your major trade partners border you or are accessible by land.

Consider that in the West for America, you have California (one of the world's largest economies today if it were its own separate country), multiple high quality ports (San Diego Bay, San Francisco Bay, etc.) to the Pacific and thus to the rest of Asia for trade. Likewise, land in the west provided an inhabitable climate for people to relieve population pressures in the east and for increased agricultural production.

Finally, the distance between the American east and west is much less than Russia to its Far East - the railway simply could do more transporting goods and people because of those shorter distances, and so the US benefited far more from its railway to the West.