Cincinnati Southern Bridge

The Cincinnati Southern Bridge carries Norfolk Southern Railway’s Cincinnati, New Orleans & Texas Pacific Railway over the Ohio River between Cincinnati, Ohio, and Ludlow, Kentucky.

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History

Cincinnati Southern Railway

The Cincinnati Southern Railway is a railroad that operates between Cincinnati, Ohio, and Chattanooga, Tennessee. The city of Cincinnati wholly owns it, the only municipality in the country to own an interstate railroad. The Cincinnati Southern was leased to the Cincinnati, New Orleans & Texas Pacific Railway (CNO&TP) in 1881, which fell under the control of the Southern Railway in 1893, which eventually became Norfolk Southern Railway (NS).

The construction of the Cincinnati Southern was spurred by a shift in shipping methods around Cincinnati which favored major rivers and canals in the 1800s. The advent of railroads led the city to formulate plans to develop its own line in 1835. ³ The city sent a delegation to the Great Southwestern Railroad Convention in July 1836, but an economic downturn in 1837 put a stop to the project. In 1851, the Ohio Constitution was amended to prevent cities from forming a partnership with a stock corporation which prevented the city from constructing the railroad.

An attempt was made in 1859 at raising $1 million in cash from private entrepreneurs that would be awarded to the Cincinnati, Lexington & East Tennessee Railroad in exchange for establishing a route between Cincinnati and Knoxville, Tennessee. ⁴ The Civil War halted any development of that proposal; however, General Burnside offered a plan to establish a military railroad to the south, which received a recommendation from President Lincoln to Congress in December 1861. Surveys were made, but nothing further came about.

With the passage of the constitutional amendment in 1851, Cincinnati proposed constructing and owning the railroad outright. ³ This proposition, by Edward A. Ferguson, was proposed in 1868 and passed on May 4, 1869. On June 4, the Cincinnati city council adopted a resolution designating Chattanooga as the southern terminus of the proposed Cincinnati Southern Railway. ⁴ The citizens voted overwhelmingly on June 26 in favor of a $10 million municipal bond issue to begin construction of the north-south line.

1877 Bridge

Construction of the Cincinnati Southern Bridge over the Ohio River, connecting Cincinnati and Ludlow, began in 1869 and was finished in December 1877. The total cost of construction was $811,683. ¹ The bridge was designed by Jacob H. Linville from Pittsburgh, Pennsylvania, and built by the Keystone Bridge Company, of which Linville was a part. ⁷

The new crossing measured 3,240 feet in length and featured a Linville-variant Whipple through truss as the main span, which measured 519 feet in length, making it the longest of its kind worldwide upon completion. ^{2 5 6 8} The bridge consisted of three other river spans. Two of these spans were Whipple through trusses, each measuring 300 feet long. ⁷ A swing Whipple through truss span near the Kentucky shore had a length of 370 feet. The purpose of the swing span was to be utilized during periods of high water when there wasn’t enough vertical space for boats to pass under the main span, although it was seldom if ever, used. ⁹

Additionally, the bridge included eight approach spans, consisting of three 150-foot through trusses, two 70-foot through trusses, and five deck trusses comprising three 150-foot trusses and two 100-foot trusses. ⁵

In the early 20th century, it became evident that the Cincinnati Southern Bridge had become outdated. Due to weight limitations, trains had to be disassembled and transported across the river by locomotives weighing no more than 65 tons. ⁷ Furthermore, the cars were restricted to a maximum gross weight of 115,000 pounds. Another issue with the bridge was its congestion, mainly caused by having only a single track. ^{5 6 7}

1923 Bridge

Extensive reconstruction work was undertaken on the Cincinnati Southern Bridge between 1921 and 1922. For this endeavor, the railroad enlisted the services of Ralph Modjeski as the consulting engineer, the Foundation Company as the substructure contractors, and the American Bridge Company as the superstructure contractors. ⁶

Throughout the reconstruction process, which began on July 15, 1921, ¹⁰ the original bridge remained open to traffic, although there were restrictions on the weight of cars. ^{6 10} The substructure and piers were widened, and the superstructure was reconstructed around the existing trusses. To transport materials like steel, temporary railroad tracks were installed outside the trusses, secured by brackets and stringers.

The rebuilt Cincinnati Southern Bridge opened to traffic several months ahead of schedule on May 1, 1922. ¹⁰

The rebuilt bridge had a similar total length of 3,240 feet but maintained a main span length similar to the original bridge. ⁵ One notable change was the replacement of the swing span with a through truss vertical lift span. ^{6 7} This 365-foot-long lift span could only be raised 12 feet to accommodate tall boats during high-water events. Upon completion, the lift span weighed three million pounds, making it the heaviest in the world at that time. Hydraulic jacks were used to raise the lift span instead of motors. Additionally, the trusses were continuous for three spans from pier three to pier six.

On the north approach, the old through truss spans were replaced by deck plate girders on masonry piers for a total length of 921 feet. ⁷ Of those, the longest span was 120 feet. A new 658-foot single-track viaduct supplemented the existing single-track viaduct.

There was a significant change in metallurgy, particularly regarding the materials used in different parts of the structure. ⁶ Silicon steel was employed in riveted members, while heat-treated carbon steel was used in the eye bars. The allowable unit stress for both types of steel was set at 24,000 pounds per square inch, which marked a 50% increase compared to regular structural steel. This change allowed for a reduction in the size of structural steel components while enabling a significant increase in the load-bearing capacity.

The seldom-used vertical lift span was permanently closed in 1976, with the infrastructure later dismantled. ³

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Gallery

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Details

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Sources

1. Kenny, Daniel J. Illustrated Guide to Cincinnati and the World’s Columbian Exposition. R. Clarke, 1895, p. 23.
2. Goodman, Rebecca. This Day in Ohio History. Emmis Books, 2005, p. 218.
3. “The Birth of an Idea.” Cincinnati Southern Railway. Article.
4. “Historical Timeline.” Cincinnati Southern Railway. Article.
5. Holth, Nathan. “Cincinnati Southern Railroad Bridge.” Historicbridges.org, 2011.
6. Henrici, F. W. “The New Ohio River Bridge of the Southern Railway at Cincinnati, Ohio.” Proceedings of the Thirty-second Annual Convention of the American Railway Bridge and Building Association, 1923, pp. 49-60.
7. “Double-Track Spans Placed on Single-Track Piers.” Railway Age, 1922, pp. 1215-1219.
8. Hall, Charles G., ed. “The Building of the Road.” The Cincinnati Southern Railway, 1902, p. 54.
9. “Is Your Answer Here?” Cincinnati Enquirer, 22 Feb. 1922, p. 3.
10. “Opened to Traffic.” Cincinnati Enquirer, 2 May 1922, p. 15.