Dear Twain-List participants--

The NY Times quotes Deputy Secretary of State Richard Armitage before the 9-11 commission as saying the following:

"The words of Samuel Clemens come to mind, and that is even though you're on the right track , you can get run over if you'r not going fast enough."

This is one attribution that I'm not familiar with.  Can anyone help me out.  Did Clemens/Twain say this? In what context?
I knew it was just a matter of time before his words were invoked by someone, but I just didn't know how they'd be construed.

--Larry Howe