• Railroad / Transit Tunnels
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Purple Line – Plymouth Tunnel

Maryland Department of Transportation Maryland Transit Administration (MDOT MTA)

The Purple Line is a new light rail line running approximately 16 miles (57 km) between Bethesda, MD and New Carrollton, MD. The line will provide direct connections to the Metrorail Red, Green, and Orange Lines, in addition to connections to MARC, Amtrak, and local bus services. The majority of the project will be at-grade except for the approximately 1,000 ft (311 m) long Plymouth Tunnel between Plymouth Street and Arliss Street in Silver Spring, MD.

Bid Tender Design Services:

Gall Zeidler Consultants developed the bid level design of the primary and final linings for the Plymouth Tunnel, which included evaluation of the geology, development of excavation and support classes for tunnel construction, and preliminary structural models.

Location:

Baltimore, MD

Date:

2014

Structure:

SEM Light Rail Tunnel

Length:

1,020 ft (311 m)

Cross-Section:

Approx. 29 ft height x 35.6 ft width (8.8 m x 10.85 m)

Geology:

Topsoil, fill with debris, colluvium, saprolite, Laurel Formation (Gneiss)

Client:

Parsons / Kiewit Infrastructure

Owner:

Maryland Department of Transportation Maryland Transit Administration (MDOT MTA)