"In the summer 1914 campaign, the Germans have a wide open western flank blocked only by obstacles and a very thin screen. All it takes to block rail movement is a unit on the rail line. More units show up later on, but I don't really see how the garrison units in the west can contain a Russian player who knows where the Germans are and who wants to use that knowledge to send out his cavalry in small groups to block rail movement and capture rear area objectives, quite possibly even triggering sudden death."
Russian 1st Army (Rennenkampf) fixes on and off continually, right through the 31st of August. Also it's not so easy for the Russians to get near the German RR lines that are quite far to the north, in fact, the few cavalry that the Russians possess will find it is impossible to cut German RR without infantry support from 2nd Army. The biggest problem the Germans face is strategic; how to extricate themselves from the battle @ Gumbinnen and to deploy their forces in such a way as to not get overwhelmed by the Russian Steamroller. Anyway that's my take on it. jonny