along with technicians, clerks, operators, and other workers. The largest of these was also the corporate headquarters, at 140 West Street on the Lower West Side, about a half mile from AT&T headquarters at 195 Broadway. The Manhattan and Bronx parts of the underground system are owned by the Empire City Subway Company subsidiary. Similar construction, on a smaller scale, went on in Brooklyn, Buffalo and other urban areas. Suburban and rural service also expanded, mostly with aerial cable or open wire plant and Strowger switches. Service crisis Forecasters in the late 1960s underestimated demand, resulting in a shortage of capacity in Manhattan, NYTel's principal profit area. Customers had to wait weeks for a new line or a repair, and sometimes minutes for dial tone on an existing line. The new 1ESS Stored Program Control exchanges had software bugs that kept them from carrying full load. Deferred maintenance choked main distribution frames (MDFs) with dead jumpers. There were not enough cables to office buildings, nor enough underground conduits to install them. Morale was poor in all levels and departments, and strikes were frequent. The company's response was to hire and train thousands of new employees and to purchase new equipment on which they could work. Underground construction took years, but emergency installation of Anaconda Carrier pair gain systems normally used in rural areas expanded service while construction was in progress. Bell Labs added processing power to their new systems and fixed the software bugs. A new wire center at 1095 Avenue of the Americas and 42nd Street relieved four others in Midtown Manhattan of part of their load, as well as providing the company with a new headquarters for the next several decades. The crisis subsided during the 1970s, decreasing the number of workers needed to facilitate the development of the industry. On February 27, 1975, a fire in the telephone building at 204 Second Avenue and East 13th Street destroyed the MDF, disconnecting tens of thousands of customers, and obsolescent switching equipment was destroyed or damaged by smoke. Located at the south end of the East Side trunk cable duct under Second Avenue, this building connects many circuits to Brooklyn which were disrupted. A Bell System mobilization dealt with the crisis, including replacing the destroyed MDF. An obsolete and recently retired exchange at the West 18th Street office, not yet melted down for scrap metal, was temporarily resurrected to