Nazi Tank Plant, Railroads Blasted By 1,150 HeaviesRenewed activities of the ,8th Air Force grew in intensity yesterday as more than 1,850 planes—1,15) of them heavy bombers—knifed at railroads and a tank factory in the Reich. Six marshalling yards in West Germany and the Herschel and Sohn works, former locomotive and truck factory east of Cologne now turning out Tiger and Panther tanks, felt the weight — of the 8th‘s bombs.S. China Sea Closed to JapsJapan has lost control of the South China Sea, principal sea route by which Tokyo fed its war machine with supplies from conquered countries, Adm. William F. Halsey declared in a press conference, summing up five months of operations since he took command of the U.S. 3rd Fleet, dispatches reported yesterday. During that time the fleet, whose carrier craft have inflicted crippling damage on the Japs, has sunk 89 enemy warships, 563 merchantmen and other vessels and destroyed 4,370 planes, of which 1,914 were shot down and the remainder wrecked on the ground, Halsey said.Announcing what amounts to a virtual naval blockade of the South China Sea; east of the Philippines and ;ouch:ng French Indo-China, Malaya and the Dutch East Indies, Halsey said: “Forces of the U.S. Pacific Fleet can go into it any time they want to.”Halsey said the fleet had contributed greatly to the reconquest of the Philippines, where, according to yesterday’s reports from Luzon, Americanfnm»s were nnlv 34 miles from ManilaBiggest target of the day was the marshalling yard at Hamm, where it is usual for 10,000 railroad cars to be handled daily along the 30 miles of tracks. Rail lines serving the Ruhr at Kassel, where the Herschel and Sohn works are located, and at Coblenz were also hit.The three other rail targets weremarshalling yards at Neiderlahnsteun, south of Coblenz, Siegen, northeast of Coblenz, and Munster, in northwest Germany.There was light fighter opposition near Bremen, with the 55th Mustang Group coming out of it with four kills on Me 109s. Other groups in the escorting force of 700 Mustangs and Thunderbolts swooped low to shoot up rail yards, airfields and road convoys.The RAF continued its renewed offensive yesterday, too, as a strong force of Lancasters, covered by Mustangs of RAF Fighter Command, blasted the marshalling yards at Krefeld, just south of Duisberg.Berlin, where evacuation of certain government offices is underway because of the Russian advances, according to reports from neutral countries, had further cause for worry Sunday night when RAF planes hit the German capital m tjiree waves, spaced half an hour apart.