Modernizing the D.C. Metro for a Growing Midtown
Washington, DC's Mid-City neighborhoods are causing problems for the city's Metro train system. During rush hour, northbound Yellow Line trains need to pull backwards along track they have already covered to accommodate Green Line trains. According to Greater Greater Washington's Alex Cox, this problem was caused by "Massive redevelopment in Mid-City that began around the turn of the century, and has continued at a frantic pace to the present day. That has meant increased demand for service along the Green/Yellow Lines at all hours."
Unfortunately, when these trains were originally designed, they were not intended to run simultaneously at all hours of the day. They share some track and, as Cox points out, adding more track is not necessarily a simple solution because of the specific features along this stretch of track including turns and tunnels that would constrict new construction. It’s likely it would be costly to construct any additional pocket track to allow the trains to run simultaneously.