Sound Transit appoints HDR Engineering for Tacoma Link expansion final design; approves contract to procure 32 double-decker buses July 28, 2016 | North America Company News Sound Transit has appointed HDR Engineering Incorporated to provide the final design for the 3.8 km (2.4 miles) Tacoma Link extension and maintenance facility expansion. The extension will connect the... This content is available to only subscribers. Username or E-mail Password Remember Me Forgot Password