The Second Avenue Subway, which has provisions for communications-based train control (CBTC), was built to relieve pressure on the Lexington Avenue Line () by shifting an estimated 225,000 passengers. In addition, CBTC installation on the Flushing Line is expected to increase the rate of trains per hour on the , but little relief will come to other crowded lines until later. CBTC on the Flushing Line is expected to be completed in September 2017. The , which is overcrowded during rush hours, already has CBTC operation. The installation of CBTC has reduced the L's running time by 3%. Even with CBTC, there are limits on the potential increased service. For L service to be increased further, a power upgrade as well as additional space for the L to turn around at its Manhattan terminus, Eighth Avenue, are needed.