The Matanuska-Susitna Borough (MSB) and the Alaska Railroad Corporation (ARRC) jointly propose construction and operation of a new rail line to connect the Borough’s Port MacKenzie to ARRC’s rail system. The Port Mackenzie Rail Extension involves 32 miles of new rail line from Port MacKenzie to the ARRC mainline just south of Houston, Alaska. The line will ultimately provide improved rail transportation between the Port and Interior Alaska, expanding the regional transportation network. Following National Environmental Policy Act review, the Surface Transportation Board authorized the ARRC to build and operate the new rail line in December 2011. Construction on the first of six construction phases began in 2012.