Rail freight has gone through marvelous improvements over the last thirty years. It's come a long way. It had to. It was near dead half a century ago, with its share of national freight dropping from 60% in 1950 to under 30% by 1980, and going to near 0% for passenger transport. Rail will never again be our primary national mover -- unless we kill off our highways, intentionally or not, and unless we start laying railroad tracks all over the country, at which point everyone will be complaining about rights-of-way takings being given to private railroads. (In the land grants of the 19th century, the railroad industry was by far the largest recipient of public concessions ever.)
Just as rail brought about in the 19th century, the economic gains brought by the motor vehicle in the 20th century are incalculable. Those gains cannot possibly be sustained, much less repeated, by our current rail system -- or our current highway system. That rail carriers are scrambling to figure out how to move more goods on existing lines is proof alone that, whatever the "efficiency" within the system, its overall capability has hit a wall. It's like getting a few extra horses out of an engine. Rail cannot, will not, and should not be a fall back for highways.
That article you cite by McCullough says the exact same thing. You might have spared us all the statistics and just shown us the article's introduction and conclusion (highlights mine):
[From the introduction]So the author and I agree: while rail freight has made fantastic gains in internal efficiency, as a matter of proportional overall economic contribution the system is showing no gains. I disagree with him, however, that overland transport cannot be improved. It can and must be.
The focus of U.S. transportation policy in the 19th and 20th centuries was on extending the benefits of transportation to more locales and to more citizens. The focus of policy in the 21st century must also be on reducing the costs of transportation. Current transportation costs associated with safety, congestion, sprawl, and pollution are large. Future costs associated with scarcity of petroleum could be cataclysmic.
The railroad network is a national asset that could be used to reduce the costs of transportation. This paper has two aims consistent with that possibility. The first is to describe the efficiency improvements that the railroad industry itself has made in the past few decades. The second is to describe the role that rail network could play in a more efficient overall national transportation system.
...
IV. Conclusions
We still lack the data necessary to define the proper role of rail passenger service in the U.S., but it is clear that freight railroads have an allocative efficiency advantage in various markets. Though freight railroads have made significant gains in productive efficiency, rail freight is still one of the slowest growing modes of transportation in the U.S. Figure 8, based on National Transportation Statistics from BTS, shows that since 1980 rail freight vehicle-miles-traveled (VMT) has actually grown less rapidly than highway freight VMT or even rail passenger VMT.
Below is how rail stands as compared to trucking in usage. While from 1997, the trends since then are the same. And again, we're ignoring passenger transport altogether, something that private rail has entirely abandoned:
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Table 1-51: Growth of Freight Activity in the United States: Comparison of the 1993 and 1997 Commodity Flow Surveys
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