Detailed Description of Possible North Bethesda Alignment
The Automated Microbus system would run from a western terminal at Westfield Shoppingtown Montgomery Mall to an eastern terminal at the Grosvenor-Strathmore Metrorail station, a straight-line distance of approximately 2.2 miles (3.4 km). Three short lines serve Rock Spring Corporate Park. All lines are two way, and all stations are at the ends of lines. More than half the alignment and most stations are at grade. Two sections of Microbus roadway along the I-270 West and East Spurs pass under Fernwood Road and Old Georgetown Road as shown in the diagram below. In the images of the system, these sections are shown as solid black lines, the same as three short underpasses near Old Georgetown Road.
Because of uneven terrain, flooding considerations, and environmental concerns, some of the at-grade alignment would actually be built on pilings. The at-grade alignment is isolated from pedestrians by fences.
From the western terminal, the alignment runs at grade along the edge of a Montgomery Mall parking lot, and crosses the I-270 West Spur on a new bridge parallel to and just south of the existing Fernwood Road highway bridge. It then turns 180 degrees through a downgrade to connect to a "T" intersection. The mainline of the T runs north and south along the east side of the I-270 West Spur. The southbound line terminates at a station near Fernwood Road. Northbound, it passes under the Microbus route and the adjacent bridge.
After the alignment passes under the Fernwood Road bridge, it proceeds north along the east side of the I-270 West Spur. A "T" intersection connects a short branch running east to a station at Rockledge Drive. The main line continues north and turns northeast and then east to run along the south side of the I-270 East Spur. Before the alignment reaches Rockledge Boulevard, a "T" intersection connects a short branch line running south to a station at Rockledge Drive. The main line continues east under Rockledge Boulevard in a structure similar to a pedestrian underpass.
The Microbus route runs east at grade, but before reaching Old Georgetown Road it turns northeast to pass under an off ramp of the I-270 East spur. It then crosses under the Old Georgetown Road bridge in a triangular space currently unused, as shown in the diagram at the right. The line then briefly turns to the southeast to pass under the on-ramp from Old Georgetown Road northbound to the I-270 East Spur eastbound. This rather complicated routing reduces the number of linear feet of tunnel required, compared to simply tunneling under Old Georgetown Road. All of the three underpasses are located above the level of the nearby I-270 East Spur, and should be well above the water table.
The alignment proceeds east along the south side of the I-270 East Spur for approximately 3000 ft (900 m). It turns northeast to cross the East Spur on a new bridge, and remains elevated as it runs along the south side of Tuckerman Lane. The line crosses MD 355 and terminates at the Grosvenor-Strathmore Metrorail Station on an upper level of an existing parking structure.