FEAF commander General George E. Stratemeyer had emphasized attacks on the rail net since its capacity for troop and supply movements was much greater than that of the roads; he had stressed in particular the destruction of railroad bridges. To date, results had been less than originally hoped for, because of both an overestimate of FEAF capabilities and an underestimate of PVA/KPA countermeasures. But as the attacks continued, a principal point in the selection of targets remained that dropping the railroad bridges and keeping them unserviceable would leave the PVA/KPA with no usable stretch of rail line more than long. On 5 March General Ridgway had his five-day forward supply levels in all items except petroleum products. Severely taxed railroad facilities would need two more days to complete petroleum shipments. In the meantime, intelligence operations provided no confirming clues that a PVA/KPA offensive was an immediate threat. In evaluating the PVA/KPA's most likely course of action Colonel Tarkenton predicted that they would defend the line he had described at the first of the month, but with changes in the frontline order of battle. The PVA 39th and 40th Armies appeared to have withdrawn from the front. This withdrawal left the KPA I Corps and PVA 50th Army in the western sector of the line, the 38th, 42nd and 66th Armies in the central area, and the KPA V, III and II Corps and 69th Brigade in the remaining ground to the east. With supply requirements all but met, IX and X Corps finishing their advance to the Arizona Line, and no clear indication of an imminent enemy offensive at hand, Ridgway on 5 March ordered Operation Ripper to begin on the morning of 7 March. Objectives The final objective line of the operation, the Idaho Line, was anchored in the west on the Han River east of Seoul. From that point it looped steeply northeastward through the eastern third of the I Corps' zone and almost to the 38th Parallel in the IX Corps’ central zone, then fell off gently southeastward across the X Corps and ROK zones to Hap’yong-dong, an east coast town north of Gangneung. Since Line Idaho traced a deep salient into PVA/KPA territory, a successful advance to it would carry the Eighth Army, in particular IX Corps in the center, into an area believed to hold a large concentration of PVA/KPA forces and supplies. Prize terrain