Hmmm. Interesting.
"Highway Patrol" was on the 1982 Bruce Springsteen Nebraska album, which I think is the Springsteen album that is closest to the "folk" genre (excluding the recent Seeger tribute albums). "Highway Patrol" has this stanza:

Me and Frankie laughin' and drinkin'
Nothing feels better than blood on blood
Takin' turns dancin' with Maria
As the band played "Night of the Johnstown Flood"

There's a (very forgettable, IMHO) rock song called "Night of the Johnstown Flood" on a 1988 album called Cities We're Not From by a group called The State Lottery (click to hear).
There's another song, more of the bluegrass genre, called "Night of the Johnstown Flood" on a 2010 album called Simpler Times by the Rock Creek Jug Band of Chico, California (nice album, by the way).
So, we have TWO different songs titled "Night of the Johnstown Flood," recorded in 1988 and 2010 - but the Springsteen album that talks about a song called "Night of the Johnstown Flood" was issued in 1982.

So, was Springsteen talking about a real song, or did he make it up?

-Joe-


P.S. "Heart of My Heart" is a good example of a song about a song that may not exist. Is "Highway Patrol" another?