3b4 CHAPTER Il, SECTION 2 es Figure 2-16. Gene - Helen - Irene A tight construction schedule developed, resulting in an extremely high production re- quirement. The compressed timetable was pri- marily due to the receipt of approved working drawings later than had been anticipated. This also affected the material situation, since specially designed items could not be ordered until drawings were well advanced or at least until design criteria were firm. Construction on several stations was further complicated by receipt of changes in approved drawings after construction had started. In order to complete stations as scheduled, it was necessary to work more overtime than was expected. Two. shifts were required in the construction of vacuum pipe arrays at Yvonne. Substitution of materials available at the Jobsite and some improvisations, combined with the expeditious supply of critical items through greatly increased use of air transport, made it possible to maintain satisfactory progress. Over-all progress of Job 1 construction is illustrated in Chart 2-1. Construction progress of Expendable Test Facilities, based on the Estimated Operations Schedule is shown by Chart 2-2, and 2-3. Previous discussion noted the need for revising the operations schedule as the scope of work increased. By 4 November, the majority of criteria was considered firm and progress was then reevaluated based on the revised schedule issued on this date. This is reflected in Chart 2-3 which shows a drop in the predicted progress from 43 per cent in November 1955 to 36.93 per cent in December 1955. Basically, this indicated that a large portion of the work load was shifted to the latter months of the construction phase of the Operation. Throughout the early months of 1956, very satisfactory progress was achieved. Every effort was made to complete various construction projects early enough to permit beneficial occupancy by the Users so that their instrumentation could be accomplished in time to meet target dates. Considerable overlapping of construction and instrumentation Page 2-17