If what the parent said was correct, then it wasn't merely because Sacramento was the capital, so my first guess would be wrong under that criteria.
And it makes sense they would list so many Ohio cities if major railroad hubs was the criteria. Ohio was practically the hub of the nation with major railroads running through all the cities you listed plus riverboats. California at this point was comparatively speaking still pretty much a backwater, even post-Gold Rush, and wasn't politically nor industrially significant before at least the first transcontinental railroad. No one in Congress had even worked particularly hard for the California EC votes until the Chinese Exclusion Act of 1882.
And it makes sense they would list so many Ohio cities if major railroad hubs was the criteria. Ohio was practically the hub of the nation with major railroads running through all the cities you listed plus riverboats. California at this point was comparatively speaking still pretty much a backwater, even post-Gold Rush, and wasn't politically nor industrially significant before at least the first transcontinental railroad. No one in Congress had even worked particularly hard for the California EC votes until the Chinese Exclusion Act of 1882.