 When construction on the line was halted in 1975 , three tunnel segments were completed : one from 99th to 105th Streets and a second from 110th to 120th Streets , both under Second Avenue in East Harlem , and a third from Pell to Canal Streets in Chinatown , under the Confucius Apartments complex next to the Bowery . They were not initially outfitted with track or signals . Over the next few decades , the MTA regularly inspected and maintained the tunnel segments ( spending $ 20 @,@ 000 a year by the early 1990s ) , to maintain the structural integrity of the streets above , and in case construction would ever resume . Trespassers would often camp in the tunnels until the MTA increased security . 
