Yeah, the Eastern Front in WW1 definitely had a lot of mobility to it.
In fact, it's been said that the "roots of Blitzkrieg" were forged in the East from 1914 to 1917.
From The Roots of Blitzkrieg, pg. 7, by James S. Corum (a book I highly recommend):
"Almost all of the tactical experiences of the British, French, and American armies in World War I came from the western front, where the war was dominated by the problem of attacking and defending a continuous front of strong trenches. The Germans' experience was dramatically different from the Allies' because a large part of the Imperial Army served on the eastern front, where an extremely long front, open terrain, and fewer soldiers per mile meant that the war of maneuver was a normal feature of eastern tactics. In August 1914 the outnumbered German Eighth Army, using the superior mobility of the German rail system and possessing more artillery firepower, surrounded and destroyed the Russian Second Army at Tannenberg. In May 1915 the German Eleventh Army, commanded by General von Mackensen with Colonel Hans von Seekt as his chief of staff, opened the Gorlice offensive with a short but heavy artillery barrage and rolled over the Russians with the whole army. For six weeks the Germans advanced at a rate of 6.5 miles per day, capturing 240,000 prisoners and 224 guns for a loss of 40,000 casualties."