Guthrie, son of the legendary Woody Guthrie, told CBS News he was trying to think of a way to help Katrina's victims when he heard on the news Amtrak was resuming service on "The City of New Orleans."
"I said, 'Well, there's something we can do.'"
Guthrie had a hit in 1972 with "The City of New Orleans," a song written by late Chicago folksinger Steve Goodman.
Guthrie, his family and musician friends are riding the train from Chicago to New Orleans this week and stopping to play a series of concerts along the way. All the money raised by the concerts will be used to replace lost instruments and help rebuild New Orleans' music venues, CBS said.
Guthrie's friends are helping underwrite the trip and concerts.
One of the underwriters for the first concert was Richard Pryor, who died Saturday.