Blue Ridge Railroad
Thanks to Mitch Bailey for the picture and information on this page.
A view looking out of Stumphouse Tunnel.  No trains ever ran through this tunnel as it was never completed.  This tunnel was to become part of a route from Anderson, SC, to Knoxville, TN.  The railroad made it as far as Walhalla.  Visitors can now once again go into the tunnel!  It is said that nearby Clemson University used to store cheese in the back of this tunnel....
Topo from maptech.com showing the location of Stumphouse Tunnel.  The park is located on the E side of SC 28.  The portion of the tunnel on the W side of SC 28 is supposedly inundated by Crystal Lake.
Topo from maptech.com showing the location of Middle Tunnel and Saddle Tunnel.  The ROW went along the Blue Ridge escarpment and then penetrated the Blue Ridge at Stumphouse Mountain.  There apparently would have been a trestle at Issaqueena Falls as the ROW turned to approach Stumphouse Tunnel.  If only this road had been completed - this may have been one of the most photogenic railroads spots on the east coast!
Topo from showing the location of the ROW as it comes N from Walhalla and then twists and turns to gain elevation.  Many of the cuts are still visible.  The other 2 tunnels other than Stumphouse have apparently collasped or are otherwise inaccessible.
The abortive Walhalla, SC - Knoxville, TN  "Blue Ridge Railroad" project

As early as 1836, even as the first American intercity steam powered railroads were being built and operated, schemes were being floated for building railroad links over the Appalachian Mountains between the ports of the southern Atlantic seaboard, and the communities inland around the Tennessee and Ohio valleys.  The region of "Rabun Gap", a relatively low place through the Appalachian chain in northeast Georgia, attracted much attention as a potential route. The interest was heightened when gold was discovered at Dahlonega, GA, to the west.

In 1836, former vice president John C. Calhoun led a group of businessmen, (including prominent German immigrant and Charleston merchant J.A. Wagener whose son George would build the original Blackville, SC - Seivern, SC railroad fifty years later) in plotting what they called the "Cincinnati, Louisville, and Charleston Railroad" that would ultimately link Charleston, SC, with Knoxville, TN and Cincinnati, OH.

Railroads from Charleston, SC to Anderson, SC, and from Knoxville, TN to Cincinnati were already in place by the time the group was ready to begin construction in 1854 (four years after Calhoun's death). The "Blue Ridge" project aimed to complete the connection by building through Rabun Gap and down the Little Tennessee River valley.

Construction began in 1854. Massive cyclopean piers and culverts of stone were installed in the rugged hills, as the railroad investors built for the ages with seemingly unlimited capital. No rickety wooden trusses for the Blue Ridge! The incredible Stumphouse Tunnel near Wahalla (unfortunately closed to visitor entry in recent years) remains to this day as a monument to their vision, as well as lesser works such as the Dick's Creek tunnel in Rabun County, Georgia. All this work, never forget, was done entirely by human labor using hand tools and a few draft animals.

The state of Georgia had meantime gotten into the act by chartering the "North Eastern Railroad" in 1854. It was intended to run out from Athens and join the proposed Blue Ridge line at Clayton. This would link Savannah and other Georgia cities to Knoxville and points beyond.

The railroad had only been completed from Anderson to Walhalla, SC (a town founded by J.A. Wagener), when work ceased due to the impending Civil War. Construction did not resume until 1869, and soon was abandoned again when bonds proved unsalable in the depressed postwar economy. At this point, the Blue Ridge Railroad project as originally planned seems basically to have been aborted.

A number of attempts were made to complete the line in the late 19th century but failed even though 80% of the grade was completed. (That other 20% must have been a real challenge!) Construction did commence on the "North Eastern Railroad" in 1871; this project eventually resulted in the Tallulah Falls Railroad, which took over unused Blue Ridge grade north of Clayton.

A number of schemes, involving the former Blue Ridge project and the "North Eastern Railroad" and its successors, to build rail connections to Knoxville and beyond, continued to be floated. "Black Diamond" was the name given in the 1890's to Col. Alfred E. Boone's multiple proposals that all involved Blue Ridge structures and ROW in some way. The "Black Diamond" schemes, and the Tallulah Falls line that was abandoned in 1961 as well, are both often confused with the much earlier Blue Ridge Railroad project.

The construction of the Fontana Dam, and the resultant flooding of much of the Little Tennessee Valley in the 1940's, decisively ended any lingering possibility of realizing the ambitious project proposed over a century earlier.

A number of relics remain to be seen, most notably the aforementioned Stumphouse Tunnel. A roadside park in Rabun County Ga. east of Clayton, the Warwoman Dell picnic area (originally a Civilian Conservation Corps project), contains some Blue Ridge roadbed and minor stonework. Other tunnels and structures are said to be visible in Rabun and Oconee Counties. Just north of Clayton, the Tallulah Falls Railway used "Blue Ridge" roadbed on its way to Franklin, NC.


References:

The Tallulah Falls Railroad: A Photographic Remembrance by Brian A. Boyd (1998, Fern Creek Press of Clayton, GA) includes a summary of the Blue Ridge and Black Diamond's history, and an intriguing 1854 photo of stonework in a bridge pier off Warwoman Dell that dwarfed the figure of the county surveyor at its base.

Myra Berthiaume, a descendant of John A. Wagener, was kind enough to provide the Stumphouse Tunnel photos and the connection her ancestor had with the project. She advised the author that the Stumphouse Tunnel had been closed, due to concerns about possible rockslides, in 1995. Thanks, Myra.  It is now reported that the tunnel is open again (as of late 2002)!

Memories of a Mountain Shortline, edited by Kaye Carver and Myra Queen, 2001, Foxfire Fund and Fern Creek Press. (Reissue of a 1976 Foxfire title).
A section of roadbed hugs a hillside in Warwoman Dell, Rabun County Ga., east of Clayton, above the public picnic area.
A small stone culvert is still in place under the Blue Ridge ROW in Warwoman Dell.
A stream tumbles down the hillside onto the ROW at Warwoman dell.