The Wabash is the principal river that runs across my home state of Indiana, so "the banks of the Wabash" is sort of a metaphor for Indiana as a whole. "On the Banks of the Wabash" (the song) is the official state song, in fact. (The better-known song "Back Home Again in Indiana" is unofficial; it also makes reference to the Wabash.*)
"The Wabash Cannonball" is of course about a ghost train. Like Big Rock Candy Mountain, it's a fictitious vision of hobo heaven--a train that never throws off the hobos, calls at every station in the country, and gets there before it leaves.
While there was an actual train called the Wabash Cannonball (an express run from Detroit to St. Louis that followed the Wabash river for much of the route), the train was named after the song, not the other way around. This was back when this country had actual passenger trains worth writing songs about. (Good mornin', America, I love ya.)
--M.
*on "Back Home Again": Everyone who grew up in Indiana eventually learns the song, I imagine (unlike "On the Banks of the Wabash," for which we probably couldn't even pick out the tune). Heres a nice version by some IU boys.
Back home again in Indiana
And it seems that I can see
The gleaming candlelight
Still shining bright
Through the sycamores for me
The new-mown hay sends all its fragrance
From the fields I used to roam.
When I dream about the moonlight on the Wabash,
Then I long for my Indiana home.
The Wabash, at least the stretch of it that flowed through my hometown, was a wide, mud-brown river that flooded its banks on a near-annual basis. We used to jokingly sing it as "When I think about the black stuff in the Wabash..." Or if we were feeling even less charitable, "When I think about the garbage in the Wabash," though the river was never actually POLLUTED polluted--agricultural runoff, mostly, which of course can be bad enough.
We also used to hold our noses on the line about the smell of hay. (Hay smells okay, provided it really is freshly mown, but farms in general take some getting used to, olfactory-wise (I was NOT from a farm community).)
They sing the song annually at the Indy 500, just after the Star-Spangled Banner, and just before the race director says "(Ladies and) Gentlemen, start your engines." (It's really too bad the 500 has to be an auto race. Everything else about it is absolute class, from the yard of bricks to the quart of milk.)
--M.