What was the most commonly accepted theory of the indian origin in north american?

Migrated across a land bridge from Russia to Alaska. 

This common belief has been challenged in recent years with more archaeological information coming from South America showing ruins older than any in North America. There are some historians who believe people may have come by boat and settled the land before the migration across the land bridge. 

hope that i helped :)

Native Americans ("Indians") migrated from Siberia across the Bering Strait, which during the last ice age was dry land. The exact time period isn't known (I believe the most commonly accepted date is about 10,000 years ago). Also, there were probably multiple migrations (at least three) based on linguists' analysis of current native American languages.

in the 1800s, locomotives powered by steam made transportation faster and cheaper. the resulting rapid growth of railroads led to the connection of the atlantic and pacific railroad in oklahoma city in 1897.

in the last years of the century, the improvement of steam-based engines the expansion and growth of railroads. this growth increased when the companies started to build and expand, such as the atlantic and pacific railroad, which connected new mexico with california, and missouri with oklahoma. many of these new networks were built in oklahoma, and these changes transportation henceforward.