An OY strip had been completed on 13 November at Koto-ri, but heavier engineer equipment was needed at Hagaru. Before it could be brought forward, the road from Chinhung-ni to Koto-ri required strengthening and widening. This task had already been assigned to Lieutenant Colonel Partridge, commanding the 1st Engineer Battalion. After a survey by jeep, he decided to begin operations at the highest point of the one-way dirt road. “By working down,” he explained, “we could first of all provide for what we considered to be a dangerous accumulation of snow, and the problem of land slides.... The work on the road involved a good bit of drainage in order to insure that the melting snows from day to day during the sunlight hours would not filter across and destroy the road bed. It involved demolitions and drilling and a good deal of dozer and grader work.”[335] [335] LtCol J. H. Partridge interv by HistDiv, HQMC, 25 Jun 51, 31–32. Enough progress had been made by 18 November so that armor could be sent forward to support RCT-7. Only the day before, the 1st Tank Battalion had begun functioning with its Headquarters and Service Companies at Soyang-ni, eight miles northwest of Hamhung. The road between Chinhung-ni and Koto-ri was still impassable for M-26 (Pershing) tanks until the engineers could widen some of the turns. But Lieutenant Colonel Harry T. Milne, the battalion commander, organized a provisional tank platoon consisting of two M4A3 (Sherman) tanks from Headquarters Company and four dozer tanks from Company D at Majon-dong. They proceeded without incident on the 18th to Hagaru, operating as a gun platoon.[336] [336] 1stTkBn _SAR_, 18. 1stEngrBn had been ordered to prepare the MSR for tank use on 6 Nov. CG 1stMarDiv msg to CO 1stEngrBn, 1530 6 Nov 50. Opening the mountain road to heavy traffic made it possible on the 18th to begin work on the Hagaru airstrip. Five large dozers with pans of eight cubic yards capacity arrived at the site the next day, and Company D of the 1st Engineer Battalion tackled the job of hacking out a runway from ground frozen as hard as granite. Plans called for a cut of 90,000 cubic yards and a fill of 60,000 for a 3200-foot runway. The rub was that engineering field manuals prescribed a runway of 3600 feet for R4Ds or C-47s at sea level, plus an additional 1000 feet for each 1000 feet of altitude. And since Hagaru was about 4000 feet above sea level, it could only be hoped that pilots were right in estimating that a strip of 3000 to 4500 feet might do in a pinch.[337] [337] CG 1stMarDiv msg to CG X Corps, 1229 18 Nov 50; Partridge interv, 25 Jun 51, 39–40.