Earlier this month, the Montgomery County Council passed an act to authorize the county to plan, design and construct the County's remaining section of the Metropolitan Branch Trail by 2018.
According to a document from February, phase II (as seen below) would be completed in FY 2018 - the same year DC plans to finish the Fort Totten section - along with an interim trail for phase I. The interim trail is being built because "there is no guarantee that the Ripley II project - a private project [behind which the trail will run] - will be completed on schedule." If all three sections are completed by then, the trail will then be functionally complete, with cyclists able to ride from Silver Spring to Union Station on the trail, even if that includes a few short interim sections.
The trail in Silver Spring will now be 12-feet wide (instead of 10-11) with 2 foot buffers and the whole thing will be lit at night.