Forgot the "But" part.  :-)

The railroads were primarily used to ship manufactured goods from Ohio to the Eastern and Southern markets and ship raw materials to feed those factories.  Shipping raw materials to the factories in the Northeast, e.g., coal, was also a factor.

The North didn't have the river systems.  A "fake" river system - canals - were used but rail roads out competed them when the goods had to be transported farther than 200 miles.  

For passenger service the railroads won hand's down.  

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre

Not easily deduced from the RR map is the tremendous importance of Buffalo New York.  Located on Lake Erie it was a major center of grain trading.  What "killed" the trade was the completion of the Saint Lawrence Seaway in 1959.

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre

Agreed. Rail's initial use was very much to ship products to river ports and/or to create rail portages between rivers and lakes. But the Arkansas was not navigable much beyond Little Rock and the Missouri was highly seasonal above Council Bluffs, Iowa. Rail really came into its own with the trans-continental lines begun during and finished after the Civil War.

"It is not necessary to have hope in order to persevere."

I'd say rather than infancy, US railways already entered elementary school age. For the purposes of the discussion on access to the West, the trans-Appalachian lines matter, and all three that still matter today were essentially in place (the former NYC, Pennsylvania RR, and B&O routes, though the first wasn't yet consolidated), as well as the Erie.

_{*Lunatic*, n.
One whose delusions are out of fashion.}