For the withdrawal of the Russians from Grodno there were available two railroads, one running north to Vilna and another running at first southeast to Mosty, and there dividing into two branches by both of which finally in a roundabout way either Minsk or Kieff could be reached. The Germans, of course, were eager to cut off these lines of retreat. The latter road was threatened by the forces approaching Grodno from the south. Before they reached it, however, troops from Von Hindenburg's group on September 1, 1915, cut the Grodno-Vilna railroad at Czarnoko. On the same day some of the western outer forts of Grodno fell, Fort No. 4 being stormed by North German Landwehr regiments and Fort No. 4a by other troops from Baden. In both cases the Russians resisted valiantly, with numerically so inferior garrisons that the Germans could report the capture of only 650 Russians. After the fall of these two fortified works the balance of the advanced western forts of Grodno were evacuated by the Russians. This, indeed, was the beginning of the end for the last great Russian fortress. On September 2, 1915, Grodno was taken by Von Hindenburg's army after a crossing over the Niemen had been forced. The Russians, however, again had managed to escape with their armies. The entire lack in the official German announcement of any reference to the Russian garrison of Grodno suggests that there was no garrison left by the time the Germans took the fortress. In spite of this fact, however, the Germans of course continued to capture Russians in fairly large quantities for, naturally, numerous detachments lost contact with the main body during the retreat. With the fall of Grodno the next objective of the German troops became Vilna. Indeed, on the very day of Grodno's occupation, German cavalry reached the northwest and western region immediately adjoining Vilna, in spite of the most determined Russian resistance. These, of course, were troops that had not participated in the drive against Grodno, but during that time had been fighting the Russians farther to the north, and now that Grodno was no longer to be feared, started a drive of their own against Vilna. Vilna is second in importance among Polish cities only to Warsaw itself. By September 8, 1915, detachments of General von Eichhorn's army had reached Troki, hardly more than ten miles west of Vilna.