It helped finance the construction of the Transcontinental railroad. As did nearly 60 million worth of 30 year bonds the Gov. floated to help pay the construction costs. Lincoln occasionally did work for the Illinois Central RR.
Don’t think he was on a permanent retainer for them. Nor do I know if he worked for any other railroad.
That it was beneficial to the larger public is clear, but what is not clear is whether or not this was the prime consideration in the government getting this involved with the doings of industry.
Lincoln's philosophy of "Mercantilism" did benefit the public eventually, but it benefited the powerful people first. As I've gotten older, i've become cynical as to which master our government serves first.