Summary: This digest summarizes the 12th study mission performed under Transit Cooperative Research Program (TCRP) Project J-3, "International Studies Program." The report includes information on the cities visited, lessons learned, and discussions of policies and practices that might be applied in the United States. Mission 12, the German track-sharing study mission, took place between June 15 and July 2, 2000. The report is organized as follows: Introduction; Background and Policy Overview; Track-Sharing Relationships to Economic and Urban Development; Design; Technology; and Conclusions Drawn and Lessons Learned.