I read in Welt Kompakt last Friday that Deutsche Bahn have promised to reduce the rail travel times between Berlin and Munich to just 3.5 hours.
No further details were given, such as when this would happen or how. But if true it would make travelling by rail a serious alternative to flying between these two cities.
Flights between Munich and Berlin currently take 1:05 hrs. Factor in a 40 minute commute to the airport at either end, plus boarding times and security checks, and door-to-door travel time easily approaches three to four hours.
The current fastest rail times take 5:59 hrs, including one change at Nuremberg. From 10.Dec.2006 this will be reduced to 5:42 hrs due to the opening of a faster connection between Munich and Nuremberg. From the same day, travel times between Munich and Frankfurt will be reduced from 3:31 hrs to just 2:54 hrs. See: ICE-Züge machen Billigfliegern Konkurrenz
Further stretch-by-stretch track improvements are continually being made. These allow the trains to travel at 300Kmh. See: ICE-Strecke Berlin- München über Erfurt wird beschleunigt weitergebaut