Metro is eliminating 100 positions from its construction office, more than a third of the department, as part of an ongoing restructuring to close a $116 million shortfall in next year's budget, agency officials said recently. The construction office is part of the chief engineers and project management department, which has a 281-member staff. After 30 years of expansion, the transit agency is no longer building rail lines and stations, some have questioned the need for so many construction personnel at a time when Metro's resources are strained.