Carl Sandburg

I WAITED today for a freight train to pass.   
Cattle cars with steers butting their horns against the bars, went by
And a half a dozen hoboes stood on bumpers between cars.   
Well, the cattle are respectable, I thought.   
Every steer has its transportation paid for by the farmer sending it to market,
While the hoboes are law-breakers in riding a railroad train without a ticket.
It reminded me of ten days I spent in the Allegheny County jail in Pittsburgh.
I got ten days even though I was a veteran of the Spanish-American war.
Cooped in the same cell with me was an old man, a bricklayer and a booze-fighter.   
But it just happened he, too, was a veteran soldier, and he had fought to preserve the Union and free the niggers.
We were three in all, the other being a Lithuanian who got drunk on pay day at the steel works and got to fighting a policeman;   
All the clothes he had was a shirt, pants and shoes—somebody got his hat and coat and what money he had left over when he got drunk.

in 1897, Sandburg decided to be a hobo for a while, riding boxcars through Iowa, Missouri, Kansas, Nebraska and Colorado.

He was a veteran of the Spanish-American war, though he did not see action.