It was not until 10 October that the northern Rumanian armies were forced back to the Moldavian border; and all Falkenhayn's efforts to debouch from the central passes towards Bukarest were defeated by Rumanian valour. Nor was he more successful against Moldavia, and November arrived with its promise of snow to block the mountain-routes before he had advanced more than four miles into Rumanian territory. Mackensen, too, was held up in the Dobrudja, and a month's inactivity was only relieved by rival raids across the Danube. But by 20 October he had received reinforcements in the shape of two Turkish divisions and one German. The Russo-Rumanian line was broken, and on the 21st the railway between Constanza and Tchernavoda. Constanza was abandoned on the 22nd, its stores of oil and wheat being burned, and on the 25th a span of the great bridge at Tchernavoda was blown up by the retreating Rumanians, while the Russians hastily withdrew thirty-five miles to Babadagh. Here on 1 November Sakharov arrived to take the command with several new divisions, for Alexeiev did his best to redeem the failings of his Government, and a counter-offensive was begun. On the 9th Sakharov recaptured Hirsova, and by the 15th he had advanced to within seven miles of Mackensen's lines defending the Constanza railway. But he was too late, for the Rumanian defence which had held north and south in the central zone was crumbling fast in the western salient. Having failed along the direct route to Bukarest, Falkenhayn now concentrated his efforts on the passes west of the Törzburg; but he had little success in October. Two columns which crossed the mountains east of the Roterturm Pass and made for Salatrucul were flung back with heavy losses on the 18th, and Falkenhayn transferred his main attack to the Vulcan Pass still farther west. But he kept up his pressure from the Roterturm down the Aluta valley in order to detain there the Rumanian reinforcements which the extension of Lechitsky's line into Moldavia had released for service in the West; and in the first week of November his troops were threatening Rymnik. But south of the Vulcan they had come to grief at Targul Jiu, where on 27 October General Dragalina, with inferior numbers and artillery, won the most brilliant success of the campaign. Unfortunately he died of his wounds on 9 November, and with fresh reinforcements and guns the Germans under Falkenhayn's eyes resumed their advance on the 10th. Their progress was stubbornly contested, but on the 21st they entered Craiova on the main Rumanian railway, thus cutting off the western part of Rumania from the capital and isolating the army defending Orsova and Turnu Severin. Presently it was surrounded, but for nearly three weeks of gallant effort and romantic adventure it eluded its fate and only surrendered at Caracalu on 7 December after the fall of Bukarest.