They used to tell me I was building a dream
This is an oblique reference to the American Dream.
For some Americans, the decade preceding the Great Depression was a time of great prosperity and growth. In the process of recovering from World War I—and partly fueled by the economic stimulus that tends to accompany war—the U.S. economy was exploding with investment and innovation.
The U.S. had already climbed to the top of global production during the Industrial Revolution. And those who labored to build this new America, many of them immigrants from many parts of the world, were supposed to be sold on a dream of success and prosperity for all.
Of course, even during the Roaring '20s and before the Depression, plenty of people, especially in rural America, did not have access to this dream. This man is experiencing disillusionment, while others never lived with the illusion.
When there was earth to plow or guns to bear
I was always there right on the job
All the roaring economic success of the 1920s actually marked an early death toll for agricultural economies.
For this song's narrator, working the land and fighting in the war are two essential American acts. But by the advent of the Great Depression in 1929, the most essential American form of work was in a factory, not on a field.
Even before the 1920s, the Industrial Revolution had turned agricultural workers in the U.S. into a minority of the workforce, rather than the vast majority they had once represented. In any case, the Depression era still placed a nostalgic value on the idea of working the land. Then, as now, there was also a patriotic value placed on fighting in any of the country's wars.
Why should I be standing in line
Just waiting for bread?
Herein lies the rub.
The song's narrator has given all this to his country.
And for what? To find himself standing in one of the Great Depression's now infamous bread lines, the origins of what we now call soup kitchens.
These images of men in suits waiting for rations have become some of the most basic symbols of the Great Depression in our collective memory. Thousands of people flooded into the cities during the Depression era as farms shut down and urban centers had slightly more resources.
Once I built a railroad, now it's done
Brother, can you spare a dime?
Here the narrator further hypes up his "everyman" status, placing himself at the building of the transcontinental railroad.
He's also fought in wars and worked the land. A lot of different tasks for a man of relatively few years, huh?
In any case, the lyrics strike on yet another basic source of both pride and nostalgia for Americans of the earlier 20th century: the railroad. The construction of a railroad that reached all the way across the country beginning in the 1860s represented the extension of U.S. conquest of Native American lands and the conclusion of manifest destiny, or the belief that white European immigrants had a God-given right to go west across the continent and take over the land by force.
The railroad was proposed in 1845, started in 1860, and a new round of expansion began in 1880. It allowed for the rapid transportation of goods and people across the entire country, enabling industrial innovations that depended on long-distance shipping.
But the process also exploited the labor of thousands of Chinese workers, among others. Railroad work was extremely dangerous and generally relegated to the most marginalized workers. In 1882, the Chinese Exclusion Act prohibiting all Chinese immigration was a real slap in the face to those who had just toiled away to build the railroad. In addition, constructing the railroads frequently involved the forceful removal of Native Americans from the land the rails were built on. Many native tribes were decimated, and those who survived were displaced to isolated reservations with few resources.
Maybe the 50+ years that passed between the actual days of railroad construction and the 1931 composition of this tune allowed for this period in U.S. history to seem a bit more ideal than it actually was, at least for some.
Once in khaki suits, gee we looked swell
Full of that Yankee-Doodly-dum
Half a million boots went sloggin' through Hell
And I was the kid with the drum
The khaki suit was the look for U.S. soldiers in World War I.
The half a million boots that went "sloggin' through Hell" also refer to the boots of the U.S. infantry in World War I. Two million Americans fought in the war, at the time considered the greatest and most tragic war in world history, and 50,000 Americans died.
Yes, we know, neither of those give us the math for half a million boots—that would be 250,000 boot-wearers, right? Thankfully, the art of songwriting is not as precise as the art of historical reporting.
The songwriter's point here seems to be that he fought bravely in a war, and now he's broke and struggling. It sure doesn't seem fair, but it sure does sound familiar.