In western Korea, good rail transport into Munsan-ni and an adequate but not all-weather road system improved the division’s logistical situation. Greater storage facilities also existed in the JAMESTOWN rear supply areas than in the X Corps sector just vacated by the Marines. Division motor equipment did not suffer any appreciable damage due to the rigors of the MIXMASTER transplacement. Vehicle maintenance also presented a favorable outlook, due to the expected decreased use during the period of positional warfare. On the other hand, an unduly large number of tanks developed engine troubles in March, which were traced back to defective oil cooling fans. This condition was corrected in April and May by installation of new fan assemblies. Guns of the 1st Tank Battalion immediately began to render valuable support to Marine frontline regiments with the division’s new assignment in the west. Companies A, B, and C were placed in direct support of the three forward infantry regiments. Company D drew the reserve mission, which included tank-infantry training with the 7th Marines and preparation for reinforcing division artillery fires. Tank companies were used almost daily in the forward sectors for destruction by direct fire of the Chinese MLR fortifications. For such missions the M-46 tanks, equipped with high-velocity 90mm guns, lumbered forward from secure assembly areas to the rear of JAMESTOWN to temporary firing positions on the line. After pouring direct fire on preselected targets and completion of the fire mission, the armored vehicles then returned to the rear. Less frequently, a five-vehicle tank platoon accompanied a reinforced rifle platoon and conducted daylight reconnaissance missions of forward areas to engage the Chinese and to gain intelligence about enemy positions and terrain. During April six such tank-infantry patrols, all in the KMC regimental area, failed to establish direct contact with the enemy but did draw mortar and artillery fire. Marine artillery, which had been receiving its share of attention from Communist field guns,[61] was faced by problems in two other respects. Although the enemy held only four more artillery weapons than did the Marines, General Seiden still lacked the ability to mass artillery fires to the same degree as did the Chinese.[62] This limitation stemmed directly from the wide physical separation of 11th Marines batteries and the frontline infantry regiments being supported. A second problem, the loss of qualified forward observers--reserve officers due to return to the States for release from active service--forced the 11th Marines to begin a school to train infantry officers for this function. To make the course realistic, all firing was done at live targets.[63]