Transactions of the American Society of Civil Engineers, vol. LXX, Dec. 1910: Tests of Creosoted Timber, Paper No. 1168

In Short

This professional engineering report presents the findings of a rigorous strength-testing study conducted in 1909 on southern pine timbers that had served for 26 years in a New Orleans railroad trestle. By comparing the mechanical properties of these aged, creosoted beams to standard values for new, untreated timber, the work provides empirical evidence for the long-term efficacy of chemical preservation in semi-tropical environments. It remains a foundational reference for historical preservationists and engineers interested in the material science of aging infrastructure and the evolution of wood-treatment standards.

The Story

The investigation begins with a fundamental question that plagued early twentieth-century infrastructure engineers: while creosote treatment was known to prevent decay, did it fundamentally alter the structural integrity of the wood over long periods of service? To answer this, researchers turned to a 26-year-old railroad trestle located near New Orleans, an environment defined by high humidity and significant annual rainfall—conditions that would typically reduce untreated wood to rot in a fraction of that time. The subjects of the study were southern pine stringers, salvaged from the trestle to see if they still possessed the strength required for modern load-bearing applications.

The process of the study is one of systematic destruction. The researchers cut the salvaged timbers into manageable 15-foot sections and subjected them to controlled bending tests using a 100,000-pound capacity machine at Tulane University. By applying concentrated loads and measuring the resulting deflection with precision, the engineers established specific data points for each beam’s elastic limit and its ultimate failure point. They carefully noted every irregularity, such as existing bolt holes and internal wear patterns, treating the wood not as a perfect material but as a seasoned, imperfect component of a larger system.

The results, presented in exhaustive log tables, reveal a surprising durability. Despite decades of exposure to harsh Southern weather and the physical stresses of heavy train traffic, the wood remained remarkably sound. The data shows that while the creosote oil had mostly leached out of the heartwood, it had successfully penetrated the sapwood, leaving the structural fibers largely uncompromised by the decay that would have destroyed untreated wood.

The report concludes by placing these experimental results within the broader context of the American engineering industry at the time. By comparing their findings with contemporary data from the U.S. Department of Agriculture’s Forest Service, the authors argue that their results reinforce the existing understanding that creosote does not inherently weaken wood, provided the treatment process avoids excessive steam pressure. The study serves as a definitive validation of the industrial standards that had been in place for decades, essentially proving that the "heavy quality" creosote oil used in the late 19th century was as effective as the industry hoped it would be. The narrative ends not with a dramatic discovery, but with a settled consensus: properly treated timber is a reliable, long-lasting material for the most demanding civil engineering tasks.

How It Unfolds

The problem defined The inquiry opens by establishing the lack of empirical information regarding the long-term effects of creosote on the structural integrity of timber. It frames the study as a necessary bridge between theoretical chemistry and the practical needs of railway engineers maintaining aging wooden bridges.

The methodology established The text details the specific procurement of 26-year-old southern pine specimens from a New Orleans trestle, ensuring the sample reflects authentic service conditions. It then describes the precise laboratory apparatus, including the use of a Riehlé testing machine and specific roller-support setups designed to prevent premature shearing during the bending process.

The data recorded A series of exhaustive tables log the performance of each beam, tracking load, deflection, and the specific point of structural failure. These tables provide the raw, unvarnished history of each piece of wood, capturing both the successes of the material and the influence of past bolt-hole modifications.

The synthesis of results The concluding section compares these aged specimens against established national benchmarks for untreated pine. It confirms that the preservation process successfully resisted the climate, allowing the timbers to maintain performance metrics that compare favorably with modern, untreated materials.

The People

While the report is written in the impersonal, objective voice of civil engineering, it reflects the professional concerns and standards of a specific group of experts. W. B. Gregory, acting as the primary investigator, serves as the voice of a pragmatic profession looking to ground their design decisions in hard science rather than conjecture. He represents the cohort of engineers who recognized that the expansion of the American rail system depended entirely on the longevity of the materials supporting it.

Opposing these engineers are the forces of nature—the damp, rot-prone, and demanding environment of the American South. The "people" in this study are also the anonymous laborers who, 26 years prior to the tests, had treated the wood according to the strict, albeit evolving, steam-and-oil specifications. Their work—and the potential for "harm" caused by high-pressure steaming—stands as a silent variable in the study. Ultimately, the engineers and the historical timber are reconciled through the data; the study validates the work of the earlier crews, confirming that their careful adherence to preservation standards created a material that could outlive the original expectations of its own creators.

In Its Own Voice

There is very little information, however, regarding the effect of time on creosoted timber, and for this reason the results given herewith may prove of interest.

(This opening statement explains the author’s primary motivation for conducting the strength tests.)

In spite of these conditions, there was no appearance of decay on any of the specimens tested.

(This observation follows the description of the harsh, high-humidity environment where the timbers had been in service for over two decades.)

Since apparently it is present only in the openings of the cells, and does not get into the cell walls, its action can only be to retard the seasoning of the wood.

(This insight, quoted from a Forest Service circular, explains the underlying chemical theory regarding why creosote does not weaken the structural integrity of the timber.)

What It's Really About

The primary argument is that scientific testing can validate the longevity of industrial preservation techniques, transforming a "rule of thumb" into an engineering certainty. It challenges the assumption that wood is a transient, decaying material, arguing that with proper chemical treatment, it can remain a stable, load-bearing resource for decades. Underneath the technical data lies a question about the relationship between time and material integrity: can human-made chemical processes effectively halt the inevitable biological decline of natural substances? The work answers this with a firm, data-backed "yes," provided the treatment process is managed correctly. It is a document about the triumph of systematic maintenance over the natural decay of the landscape.

Why Read It Today

This report is essential for those who appreciate the aesthetic and historical value of infrastructure. Readers who enjoy industrial history, the meticulous detail of engineering archives, or the history of material science will find it deeply satisfying. It offers a glimpse into a time when engineers were actively "stress-testing" the backbone of the country’s infrastructure to justify continued use of wooden trestles in an era transitioning toward steel.

The reading experience is highly technical. You are not meant to skim this; you are meant to pore over the tables, tracking how a 6-by-16-inch beam holds up under a 50,000-pound load. The prose is dry, precise, and devoid of embellishment, which gives it a certain stark beauty. It is a rewarding read for anyone who wants to understand the literal foundation of early 20th-century travel. While the subject matter is narrow, the implications—how we build to last—remain entirely relevant. You leave the text with a newfound respect for the simple, quiet endurance of treated pine and a clear picture of how engineers in 1910 used empirical data to push back against the decay of time.