An interesting What/If.

The British empire had outlawed chattel slavery and had gone as far as interdicting the slave trade to South America, using the Royal Navy.  Could Southern slavery continued if they had become a "British puppet state?"

A "no" is supported by the fact one of the principal reasons the British Empire did not intervene was slavery.

A "yes" is supported by the fact the BE was acquiescent of the caste system of India.  From what I can gather, they didn't like it but they didn't like it enough to try to force its abandonment.  

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

Yes/But.

The US railroad system was in its infancy:

and note it was most developed where river traffic was least developed.  Moreover, one can argue the rail road's main purpose was to ship cargo to a river port.  

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

Letting the South go and building a rail/canal network rather than fighting the Civil War would have been the cheaper option for the North.  Alas for the Economic Determinists, major political decisions are, more often than not, made for other reasons.  Having said that, much of the "fury of the Northmen" in Iowa, Minnesota, and Wisconsin during the Civil War sprang from their assessment without free access to the port of New Orleans they would become impoverished.

   

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

Two fascinating books on this are Empire Express and Railroaded, both of which I read last year, and which I was too lazy to diary despite their immediate relevance to a lot of issues of interest here at ET.  Railroaded is especially good.

I forgot to comment this in general. Railroads are key in the Lost Cause narrative of Lincoln as a tool of capitalist interests (and this even found its way into "communist" accounts of US history, the source I heard it from).

When I finally checked up on the matter, the best source I found was Abraham Lincoln as a Railroad Attorney, a 17-page essay by James W. Ely Jr., a professor of law as well as history. I won't review that, but the most important counter to the Lost Cause narrative is that he represented cases both for and against the railroads, taking cases as they came.

Checking some additional sources, the Wikipedia account of the Council Bluffs visit seems severely distorted:

1. Norman Judd wasn't an exclusive lawyer for M&M.
   
2. Nor was Norman Judd merely an attorney: he was a key Illinois Republican (before that Democrat) operative and Lincoln's campaign manager. (Judd's loyalty is similar to Stanton's with respect to its negative origins. In 1854, Judd led a small group of Illinois state congressmen who broke away from the Democrats over the issue of slavery but foiled Lincoln's Senate nomination on a joint anti-slavery ticket, forcing Lincoln's Whigs to accept one of theirs instead. Lincoln however refused to treat him as a traitor, earning both the merger of Judd's anti-slavery Democrats into the Whig-dominated new state Republican party, and personal loyalty.)
   
3. Lincoln inspected no "M&M facilities" but 17 parcels of land owned by himself and Judd since 1857.
   
4. The occasion in 1859 was that Lincoln invoked an earlier agreement with Judd that Judd buy his half of the land, but with no cash at hand, Lincoln "loaned" the purchase price with fixed interest (which was paid to Lincoln's widow by 1867), retaining the lands as collateral. In short, he wouldn't profit from any future land price increases or compensation due to future rail construction.
   
5. Nor was Greenville M. Dodge an "M&M engineer" in 1859, though he did work a lot as a freelancer surveyor for M&M (alongside ventures like a bank and a coach company), and his pioneering 1850s surveys for a transcontinental railroad received private funding from Durant.
   
6. The meeting between Dodge and Lincoln was a chance meeting: Dodge, a resident of Council Bluffs, was in attendance at a public meeting Lincoln held and was introduced thereafter. The discussion was one-way (Lincoln thoroughly querying Dodge about his ideas).

A rough itinerary of Lincoln's four-day visit to Council Bluffs can be read here; the account of the Lincoln-Dodge meeting is here; details on Norman Judd's connections to Lincoln can be read here. Two bios on Greenville Dodge discussing his work in the 1850s (the second mentioning an 1858 attempt at selling the transcontinental railroad idea to East Coast financiers meeting total lack of interest) are here and here.

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