Not all Railroads were created equal.

[wausaubob]

p. 331 https://www2.census.gov/library/publications/decennial/1860/statistics/1860d-13.pdf

One can do the division and discover that not all railroads by 1860 had been built to the same standard as far as double tracking and sidings.
Not all railroads purchased the best rails for the initial build. Why should they have spent the money before the knew what their earnings would be?
Southern railroads generally spent less on building their lines. In some places they had lower labor costs, but without specific knowledge that should not be assumed.
The southern railroads were not as dense. Each line faced fewer competing railroads. But throughout the south the railroads faced the same problem: a good deal of agricultural freight could move by water transport more efficiently.

 

[wausaubob]

In fact there was very little railroad building going on the US between 1857 and 1866. What construction was added was in the southern regions.

https://alfred.stlouisfed.org/serie...tm_term=related_resources&utm_campaign=alfred

For the Confederacy that would be advantage in some locations. If rails and ties were new, and had not carried heavy traffic, they were in good condition at the start of the US Civil war. But in other locations, it might have been as favorable as the road bed may not have been stabilized, sidings added, and proper drainage of creeks and rivelets provided.
In other words, without knowing about the number and age of the locomotives, and the earnings of each road, it was futile to just make comparisons of miles of track.

 

[wausaubob]

From a population density map developed in 1880 from the 1860 data, it easy to see how the US Civil War developed as it did.

https://www.census.gov/history/pdf/General_Discussion_of_the_Movements_of_Population.pdf
The map follows after page xviii.

 

[wausaubob]

The familiar Confederate railroads map can be found here:https://upload.wikimedia.org/wikipedia/commons/d/df/Railroad_of_Confederacy-1861.jpg

 

[Lubliner]

Hey, thanks, @wausaubob. I like those population maps. Another thought I had when you were making good points above, was the lack of knowing the civil war was just ahead. For them to believe they had all the time in the world to experiment and profit by proven advancements means a lot when looking at the production rates.
Lubliner.