The good news first: since today the North-South S-Bahn tunnel is back in operation.
The bad news: this week Berlin’s S-Bahn drivers are on strike again. This means that only about 30% of all S-Bahn trains will be operating between Tuesday, May 5th and Sunday, May 10th.
During that time period, the ring is closed – no S-Bahn in operation. Instead most of the other lines will be in operation, mostly on a 20 minute schedule.
All other public transport, like Trams, U-Bahn and busses, run by Berlin’s public transport operator BVG, will be operating ‘as usual’ – which means vehicles might be quite crowded and you should probably calculate a couple of minutes on to of your ‘normal’ travelling plans.
Further details can be (again) found on the homepage of Berlin S-Bahn:
www.s-bahn-berlin.de/bauinformationen/betriebslage.htm