Entry into the Wimbachklamm is controlled by a turnstile at the entrance to the gorge. At the end of the gorge is another turnstile.  While the lower turnstile works as an entrance and exit, you can only get out of the gorge at the upper turnstile. In this respect you can go back and forth in the gorge as long as you do not leave the area at the upper turnstile. You can walk back and forth within the turnstiles as often as you like. But note when going back: Some places are narrow and during the main visiting period a relatively large number of visitors come up from below.