L&N Relocation: Two Tracks or Not Two Tracks

Brocks Gap Tunnel, 2004

CSX train crossing the Mulberry Fork Warrior River

[Photo https://bridgehunter.com/al/cullman/bh48984/}River


This material was originally prepared by the author for the Mid South Chapter R&LHS Newsletter, the Flyer.  The author would like to acknowledge the help of the late Lyle Key as well as Thomas Denney and editor Marv Clemons who provided information and graphics from their collections.  Due to space constraints in The Flyer, additional graphics and narrative are included here which were not able to be included in The Flyer.

f you are a student of Birmingham’s history you know that it was founded at the junction of two railroads to be a New South Industrial City.  And you likely know that in post-civil war Alabama, there was precious little capital for the building of railroads in 1870.  The S&NA had been saved from bankruptcy only by the efforts of James Sloss’ Nashville and Decatur RR (N&D) being offered, along with the unfinished S&NA to the L&N RR in a long term lease including the requirement that the L&N complete the railroad through the hills and valleys of north Alabama.

According to Chief Engineer John Milner’s son, as noted in Armes “Story of Iron and Coal in Alabama”, Milner would direct the layout of the line north of Birmingham to have “more curves, more curves and more stiff grade”, in order to save money.  Milner’s wife is quoted in the same story as saying “that was not the way my husband planned it, nor the way he wanted it.  It was the way he just had to make it.”

The Need for Improvements

Birmingham did grow and prosper to the point that the original line was inadequate.  In 1907, L&N President Milton Smith addressed a committee of the Alabama legislature describing the situation in which the L&N Railroad’s South & North Alabama Subdivision found itself.  This address was part of an ongoing battle royal between the L&N and the Alabama Legislature over rates, but that is another story. Smith stated,

“Take the North and South Alabama as an illustration.  It is a road originally built with limited capital through a rugged country across drainage, and when opened for traffic there was not a community of 100 persons on the line between Montgomery and Decatur.  The Alignment is crooked and the grades excessive, equivalent to more than 80 feet to the mile [1.5%].  The heaviest locomotive in use, having a tractive power of 35,000 lbs. can move but 740 train tons.”

This is believed to be the original S&NA bridge over the Locust Fork near Warrior, AL. Note the approach spans are wooden and the main span is a Fink Truss.  The piers appear to be the same as the image on the right, except caps. The piers are still standing, c. 2020.  Image from Jim Bennett collection.

This is believed to be the rebuilt bridge over the Locust Fork.  Here the approach spans appear to be an iron trestle work, and the main span is a heavier deck truss. Image from Warrior, AL Facebook page.

1895 Track Chart from Ken Penhale notes that the bridge was rebuilt in 1887 with a "205', 6" Iron V Deck and 24" beams N&S Approach, 38 spans 15'-10" each".

Smith’s point was to seek to have the legislators understand that railroads must be able to respond to traffic demands if they are able to support shipper’s needs and that improvements cost money.

By the time that Milton Smith was before the legislative committee in Montgomery, the L&N had already double tracked 14 miles  through Birmingham from Black Creek south to Oxmoor. Most of this work was done near original location with moderate adjustments in alignment and curvature.  Likewise work had been done from Decatur south to Flint about 5 miles in north Alabama, and from Calera south to Hardy [near Alabaster] about 13 miles providing double track, passing sidings and terminal facilities as reported in the Railroad Gazette.  This included old Boyles Yard opened in 1904.

Smith outlined these recent improvements to the legislators but stated,

“traffic now pressing is greater than can be moved and if the present volume of traffic is to be continued and increased, it will be necessary to reconstruct the line, reduce grades and curvature, lay second tracks… the work of reducing grades and laying second track between Oxmoor and [Alabaster], 14.4 miles has been begun at an estimated cost of $1 million.”  

Smith went on to say that the other needed improvements between Montgomery and Decatur would cost $15 million. Smith finished by saying that if capital could not be obtained “the carrier must restrict its traffic to existing facilities, that is, must refuse to undertake to move traffic in excess of its facilities.”  Birmingham’s growth would stop.

Of interest from an engineering standpoint is what and how the improvements were made.  Fortunately the railroad press of the day has provided great information.

The project mentioned above, between Oxmoor and Hardy [near Alabaster] included a new crossing of the Cahaba River and  Shades Mountain.  The old line had been completed before the Civil War to the south foot of Shades Mountain at Sydenton; the 75 foot deep cut through the mountain was not completed until about 1870.  The new line was completed in 1908 and involved relocating the mainline, a new bridge over the river and a tunnel at lower grades through Shades Mountain to replace the deep cut [now mostly filled in]. This project is covered in this website under the heading of Brocks Gap, Gateway to Birmingham.

It is noted above that improvements had been completed from Black Creek south through Birmingham to Oxmoor.  Black Creek is north of Boyles Yard and near New Castle, John Milner’s coal development built to assist the fledgling S&NA to develop new traffic.  From New Castle northward the original line swung to the northwest along Cunningham Creek and passed through some of the earliest coal mining areas of Birmingham at Morris and Warrior, crossing the Locust Fork of the Warrior River and traversing valleys and Reid's Gap to gain ground over the ridges, crossing the Mulberry Fork of the Warrior River toward Cullman.

The relocation and grade revisions are shown in this image for an article in Railway Review magazine May 9, 1914. Note the 1.25% Sand Mountain grade which is still a helper district today. There are two river bridges and two tunnels.

It is in this area that the L&N completed one of the most ambitious improvements between Birmingham and Decatur.  This was part of a larger “grade revision” project that extended from just north of Nashville, TN, south to Decatur, and then on south through Birmingham to Calera.

Athens to Decatur

From Athens to Decatur the line was relatively flat but on swampy terrain near the Tennessee River.  Bids received were higher than the L&N wanted to pay, so this line was built by company forces.  Equipment was acquired for $85,000 which included a self-propelled Atlantic Steam Shovel, 10 air operated dump cars, a modified tender to serve the shovel and provide a workshop platform, an all steel Bucyrus pile driver, a Jordan spreader, and a caboose workshop car.

This work train used small locomotives to shuttle the dump cars as required.  The Atlantic shovel was self-propelled and equipped with air brakes.   According to “The Excavating Engineer” this outfit was very successful and saved enough money compared to bids received to pay for the equipment.  The picture at right is from the Excavating Engineer, April, 1914.  The total excavation on this line segment was 385,000 cubic yards at the “Tanner cut” which was then used to build new fill on the swamp areas north of the Tennessee River.


Decatur to Bangor

The L&N didn’t have a bridge over the Tennessee River at Decatur; L&N [then and now] had trackage rights over the [Norfolk] Southern’s bridge.  The new line improved the bridge approach location on the north side of the river for L&N.  On the south side of the Tennessee River, L&N had already built extensive facilities at New Decatur, south of Decatur including yards and shops. South of Decatur for the first 20 miles the work was not remarkable.  It did improve grades and alignment to  some degree.

If you drive I-65 frequently, north of the Lacon exit, you may have noticed a siding in the trees on the east side of the interstate that often holds a locomotive.  This is the pusher for the controlling southbound grade on the L&N at Sand Mountain from Wilhoite to Holmes Gap..  The grade was and is 1.25%; civil engineers at the time couldn’t find a way to avoid it.  The SB pusher grade up the mountain is about 5 miles long. 

On the south side of the mountain, the northbound grade is about 12 miles, but at a more manageable grade of 0.5%. The town of Cullman is located on this segment of line.  Here the L&N decided to lower the old line some 20 feet right through town.  This required staged construction, relocation of the station and freight house and the construction of 5 street overpasses. 

These 5 overpasses were reinforced concrete with sidewalks on each side.  The loading was designed for a 35,000 lb. road roller plus 100 lb. per square foot.  Today 3 of the original bridges over the railroad are still in use, but are posted at 10 Ton total weight, including school buses. [Note that a full size school bus weighs about 16 tons empty!]  These overpasses are still standing in 2020.

Cullman to Birmingham

South of Cullman there were significant engineering issues to be addressed.  Most of the old line from Cullman to Birmingham was relocated to a completely new alignment.  Much of the remaining line was changed vertically so that for practical purposes, it was all new line.

The primary obstacles were the ridges at Blount Mountain and Hayden, the climb to these ridges and the major water crossings at Mulberry Fork and Locust Fork of the Black Warrior River as well as the crossing of Gurley Creek.  In addition there were many smaller streams and creeks to cross.

It is worthy of note that when the original line of the South & North Alabama was planned in the 1850’s, it was determined that it would be a line crossing ridge and valley terrain.  The mineral wealth of this district was well known and Chief Engineer John Milner knew that the original investment for the main line would be great, but that the extension of spurs and branch lines to the future mines would be easier to build when the time came.  The original competitor of the South & North, the Alabama & Tennessee River connected Meridian MS with Chattanooga and followed a much easier valley route for much of it’s length.  As it turned out, that line, which became the Alabama Great Southern did not achieve nearly the raw material traffic from the mines of the Birmingham District as the L&N.

The new line and grade was planned to climb the side of Blount Mountain, heading southwest.  This line followed the original line but at higher elevation to ascend the “mountain”.  After climbing the line turned south and two tunnels were bored.  The first, Blount Mountain, is about 1000 feet long and is unlined, being in good rock.  The tunnel was built from the bottom up, that is, the boring started at the track level and worked upward as forward progress was made.

The second tunnel, at Hayden, is about 2100 feet long but was in less sound rock and had to be concrete lined.  It was built from near the top and then excavated down to the floor as forward progress was made.  The roof was lined and then then as work progressed downward the sides are cut and lined; the upper portion has a footing behind the top of the side walls.  The south end of the Hayden tunnel encountered such poor rock that the portal was built about 150 feet into daylight, the tunnel constructed and then filled to prevent slides from coming over the top of the portal.

It is interesting to note that compressed air was used for drilling equipment and that the contractor had an air compressor plant on the old line, using iron pipe to take the compressed air to Blount tunnel and then on to Hayden, a total distance of about 3 miles.

South of Hayden tunnel, the line followed a ravine and stream bed going downhill towards the south.  The tunnel material was used to build a long fill coming down the south side of the mountain.

River Crossings

The three major water crossings mentioned above are still standing.  The Mulberry Fork bridge is north of the two tunnels described above.  It consists of three girder spans, three deck truss spans and a girder span, all open deck and all on a 3o curve.  The spans are 70’-35’-70’-118’-146’-118-70’ (rounded).  The concrete piers for the truss spans are about 60 feet tall.  This handsome bridge is visible from the old highway looking east, and has a curved lower cord on the main truss span.  [Photo is from https://bridgehunter.com/al/cullman/bh48984/}

The Locust Fork bridge is on tangent alignment and is also a combination of one deck truss span with deck girder and tower approaches.  The span arrangements are 60’-40’-60’-40’-60’-40’-80’-200’-80’-40’-60’-40’-60’ (rounded).  The concrete piers for the truss span are about 115’ tall.

The third major structure on the relocated route is at Gurley Creek.  This is a tower trestle structure with 7 plate girder spans and 6 @ 40’ tower spans.  The  span arrangements are 70’-40’-60’-40’-60’-40’-60’-40’-60’-40’-60’-40’-70’ for a total length of 680 feet.

A number of concrete arch spans were constructed as part of this project; concrete had certainly come into its own by this time period.  Earlier structures would have been constructed of cut stone masonry, including arches.  These may be found on the original routes of the S&NA as well as the N&D, as well as stacked stone box structures.  The Ross Bridge stone arch culvert in Hoover, AL, has become “famous”.

These improvements were completed by the time the United States entered WWI.  Railroad operations continued through the twenties and lanquished through the depression years.  Then the onset of WWII brought growth in traffic and industrial development.

Improvements in Tennessee

Briefly, the project in Tennessee included a new line to bypass Nashville, cross the Cumberland River on a major high bridge which still stands above Shelby Park, build Radnor Yards north of Brentwood [south of Nashville], and a new grade at present day Brentwood which lowered the line 45 feet, and may still be seen adjacent to the Brentwood interchange on I-65.

From Brentwood the L&N built a new route 98 miles south to  Athens, AL.  This “new line” would supplement the original Nashville & Decatur RR (N&D) built before the Civil War by James Sloss.  The new line included two tunnels and a pusher district of 0.9% for some 6 miles.  The new line was planned for freight traffic so the old N&D line could be used for mostly passenger traffic and local freight.  This effectively created a double track line from Nashville to Athens although on separate locations some mile apart. 

The relocation and grade revisions are shown in this image for an article in Railway Review magazine May 9, 1914.  The "old" line was the original Nashville & Decatur built for James Sloss before the Civil War.

CTC and Back to Single Track

Seeking new operating efficiencies, the L&N implemented Centralized Train Control (CTC) which involves the use of electro-mechanical systems to enable one operator to control signals and track switches (turnouts) on a large segment of railroad. 

According to Murray Klein’s “The History of the Louisville & Nashville Railroad”, the L&N’s first CTC installation was the 96 miles between Brentwood, TN, south of Radnor Yards near Nashville to Athens, AL..  This improvement was accomplished in June, 1942.  Subsequent installations focused on single track lines, as shown on this 1956 map from Railway Signaling magazine.

Typically, installation of CTC on single track lines enabled fewer passing sidings, fewer block and siding signals, and less operating and maintenance staff.   The image at left shows a CTC panel at Birmingham.  This display is located at the Heart of Dixie RR Museum in Calera, AL, south of metro Birmingham.

The double track between Athens and Calera in Alabama was one of the last segments to receive CTC. As was typical, the efficiencies of CTC enabled the railroad to remove double track, and this was accomplished by 1963 (Klein) when the entire mainline from Cincinnati to New Orleans was under CTC control. 

Ironically, when CTC was finally installed between Athens and Calera, the need for the double track main line was eliminated. Once the CTC system was in place and working, the railroad began removing the second track installed between 1908 and 1915.

In the image at the lower left, from Marv Clemons' collection, we see the results of the removal of double track south of Calera, AL, after the installation of CTC.


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