Drivin’ Hard Rain is a song written by Dave Sharp which he has performed extensively live when he played his shows with Dave Sharp and The Barnstirmers in 1991 but was not recorded for Hard Travellin’. The first release of it was in 1998 on the official “bootleg” album Hiding In Plain Sight which is a collection of songs played live, sessions and demos between 1990 and 1998.
Click on the above link for audio recording of Drivin’ Hard Rain which was recorded as part of a session for Rock Over London acoustic session September 1991 which appears on Harding In Plain Sight album