In The Battle Cry of Freedom, James McPherson says that the slave states quadrupled their railroad mileage in the 1850s, so there definitely was significant interest in building railroads in the south at that time.
Okay, getting out my copy of Railroads of the Confederacy here (italics are the author's):
"Though the Southern States, in January 1861, could claim an estimated railway mileage of 8,783 out of a country-wide total of 31,168, the whole extent of southern iron, rolling stock, and other appurtenances reflected a
capital investment of but $237, 138, 482 as compared to a national figure of $1,177, 993, 818. And Britain, whose railway development of the incipient Confederacy was reputed to have surpassed so handsomely, had devoted an even larger sum to its 'permanent way' and equipment."
Also:
"By 1861 Virginia lead all the Southern States in point of mileage...the Old Dominion reported a rail system of more than 1,800 miles. Second among the states of the coming Confederacy stood Georgia, with about 1,400. Even South Carolina could point to a mileage of nearly 1,000. Only North Carolina lagged somewhat, though they nursed ambitious projects. Tarheels had completed less than 900 miles upon the outbreak of the War Between the States."
I never intended to imply the South would be an industrial superpower. In terms of economic development by 1900, I could see it as being on par with Austria-Hungary or France. Both were mixed agrarian-industrial societies.
Understood.
I think the CSA is definitely going to take after Austria-Hungary in there being some relatively well off, industrialized (not necessarily the same thing, but related) regions but more extraordinarily poor areas within its borders - and while that may not be a recipe for revolution it's not a recipe for national stability or anything else desirable either.
Lots of room for petty regionalism to throttle what might otherwise be possible, IMO, is a general millstone around its neck - even if it obviously has to do better at that than OTL to exist in 1900 at all it's not going to be easy to tame. A Confederacy with the leadership for that not to be an issue would be so unlike OTL that we might as well be talking about "strangely enough, a 'Confederate States of America' emerged in this Al-Andalus Never Falls timeline." even if the POD is in the early 1800s.