IronArcturus: There are 9 OGG tracks in the "MUSIC" folder for Redline. I think it's clear that the music was supposed to loop for every level, but I'm not sure how to tell the game to do that.
Yes, GOG sometimes use OGG files for the CD audio, so 9 files for 9 audio tracks suggests it is all there then. So maybe the game never repeated the music tracks as per those YouTube videos? It is a possibility.
If you really do want to have constant music then you could play the OGG files in a media player and turn the in-game music off (or move the OGG files so that the game can't find them to play them). That way the media player could be used to repeat the tracks.