Most of the journeys / timestamps feature several different tracks to offer variety. If you are looking for a particular track within a timestamp, for example, the 'New Recharge 20' track featured in the PowerNap channel, you can identify which journey track is playing by looking at the bottom of the screen when a track is playing. At the bottom, you will notice small grey font and a journey track file name (used for copyright purposes.) Each journey track begins with ST and then a four digit number, followed by text. In the example of the 'New Recharge 20' track, the file name is ST3016_Music by Sound Tonics. (See screenshots below.)
If you see a different file name, and are wanting to hear the 'New Recharge 20' for example, simply tap the 'End' button on the journey play screen, tap 'Continue' until you return to the Home screen. Select the PowerNap Channel again, tap on the 'Start' button and again, look to see what file name appears at the bottom of 'journey play' screen.
(There are four different tracks available in PowerNap, so you might have to do this a few times before the track you want plays.)
Tracks available in PowerNap include ST2006, ST3001, ST3006, ST3016 ('New Recharge 20')